Table 2 A condensed summary of the data...

Table 2

A condensed summary of the data displays from the interviews in Part 2 of the study

Co	SLT	Data on each SLT's implications for the three absolute measures related to ROI	R	C	In
PumpCo	$E_{k}$	R1 explained that it would be more important that $E$ be stable and predictable rather than short and unpredictable. A predictable $E$ would result in less uncertainty and need for costly safety buffers. However, to increase the certainty in $E$ ⁠, the supplier might need to keep a higher inventory or safety capacity on its end, thus increasing cost. R1 also said that increasing the certainty in $E$ (⁠ $σ_{E} \to 0$ ⁠) enabled them to better fulfil their internal production plans $(σ_{I} \to 0)$ and thus increase the delivery certainty $(D_{σ} \to 0)$		✓	✓
	$I_{k}$	Reducing $I$ would most likely result in less buffers and WIP but would increase the need for more flexibility and investments in capacity, in line with the classic trade-off between lead time and capacity. In contrast, increasing $I$ by adding safety time would improve the possibility of levelling production		✓	✓
	$S$	Reducing $S$ might lead to increased uncertainty and disruptions, resulting in more replanning and expediting of orders. Either reducing or prolonging $S$ also has implications for the amounts of materials and resources needed in the supply system to achieve and maintain the length of $S$		✓	✓
	$D$	PumpCo focuses on low volume, delivery-unique products, with more demanding customers. Reducing $D$ has allowed PumpCo to charge premium prices for its products. R1 explained, “We have been able to charge a premium price because our $D$ is shorter than those of our competitors, and we have been more responsive in accommodating our customers” “demand” Still, PumpCo has reached a point where any possibility to earn higher revenue through a reduced $D$ is outweighed by the cost. More capacity and/or material stock should be acquired to reduce $D$ ⁠. Additionally, if an activity performed during $D$ could be minimised or eliminated, rather than reducing $D$ ⁠, the saved time could be used as time slack to increase delivery certainty	✓	✓	✓
	$A_{S, i}$	An increase in potential delivery-unique variants might lead to an increase in not only market share but also in item numbers, product range, potential suppliers and time slack, as adding complexity typically adds queue time. This would heighten the need for more planning and control, as well as time slack or mixed flexibility in terms of resources	✓	✓	✓
	$A_{D}$	R1 stated that by offering some delivery-unique solutions, PumpCo had succeeded in winning over customers from competitors, as well as being able to charge premium prices. However, PumpCo previously had issues with $A_{S}$ s being longer than D, where customer orders were lost. Moreover, when falling behind on delivery-unique orders, PumpCo responded by prioritising them. This created disturbances and queue time in production and entailed time and money in terms of planning and control. According to R2, PumpCo has now stopped prioritising orders: “We said to ourselves that we shall not go in and prioritise anything; it should be solved by itself. Suddenly, everything flowed, and we managed to reduce queue time.” To maintain $A_{D}$ ⁠, PumpCo also invested time and money in designing more stable and flexible processes for activities carried out during $A_{D}$ s	✓	✓	✓
TelecomCo	$E_{k}$	According to R3, a predictable $E$ results in less uncertainty and need for costly safety buffers. Moreover, if one knows the length of $E$ and it is always the same (stable), then they do not need to use a safety buffer at all; they will always get the material at the time they planned for its arrival		✓	✓
	$I_{k}$	$I$ can be prolonged through increased safety lead time, resulting in not only greater flexibility but also more materials accumulating. In contrast, increasing capacity makes it possible to reduce $I$ and the amount of materials accumulating		✓	✓
	$S$	Prolonging $S$ results in a system that is less responsive to changes in products or technology, where more materials and investment accumulate in the system. Prolonging $S$ ⁠, where $D$ is unchanged, also results in a longer $S - D$ segment and more uncertainty where more activities must be conducted on speculation		✓	✓
	$D$	If an activity performed during $D$ could be minimised or eliminated, then rather than reducing $D$ ⁠, the saved time could be used as time slack to increase delivery certainty. Still, R3 and R4 recognised key motives for reducing $D$ and potentially increasing the market share. However, they did not see the possibility of increasing the selling price due to their highly competitive market	✓	✓	✓
	$A_{S, i}$	Only the $A_{S}$ s that are at or downstream of the upstream end of $D$ can be used for delivery-unique offerings and possibly increase the market share. However, creating these variants will result in more item numbers and possibly increase both the volume and the mix of items in stock	✓	✓	✓
	$A_{D}$	$A_{D}$ has obvious potential for enhancing a company's ability to generate revenue. However, the complexity of planning and controlling these orders increases with more delivery-unique offerings	✓	✓	✓
LuminaireCo	$E_{k}$	Prolonging $E$ would result in an increase in raw material inventory. In contrast, in reducing $E$ ⁠, LuminaireCo might have to use faster and more expensive transportation modes and/or increase the cost of direct materials by purchasing more from local suppliers. Even so, R6 believed that an increased certainty in $E$ “could result in additional sales because we [LuminaireCo] are able to keep what we have promised [promised due date]” R5 said that increasing the certainty in $E$ $(σ_{E} \to 0)$ enabled them to better fulfil their internal production plans $(σ_{I} \to 0)$ and thus increase the delivery certainty $(D_{σ} \to 0)$ ⁠. Moreover, if $E$ could be reduced so that it would fall within $D$ ⁠, then less materials would need to be purchased on speculation, reducing the risk of being out of stock, as well as buying wrong items in terms of the demand		✓	✓
	$I_{k}$	Reducing $I$ would most likely result in less buffers and WIP but would increase the need for more flexibility and investments in capacity, in line with the classic trade-off between lead time and capacity		✓	✓
	$S$	Prolonging $S$ results in a system that is less responsive to changes in products or technology and where more materials and investment accumulate in the system. For instance, LuminaireCo is undergoing a technology transition; traditional light sources are being replaced with light-emitting diode technology. According to R5, they “have over 80 generational changes this year”, and these changes have resulted in reengineering products, sourcing new items and phasing out outdated ones. R6 provided an example: “We are acquiring things [components] now in February, and it is not until August/September that the change will take place according to plan. But in case this does not go down as planned, we might have to postpone the change until October/November […]. We also retrofit the demand by using campaigns, when we are too late with the generational change and need to get rid of components and products. Not having enough or the right materials in stock may also result in loss of sales, where customers are unwilling to wait for the products to be produced. Still, this is an indirect implication, where $D$ could not be fulfilled		✓	✓
	$D$	Reducing $D$ has obvious and strong implications for a company's ability to generate more customer orders, especially if $D$ is an order winner. R5 even said, “We get more customers because we have short lead times [ $D$ ], or we can reduce our $D$ even more, which our competitors can't” In contrast, not fulfilling $D$ would most likely result in loss of sales. Moreover, R6 argued that an increased delivery certainty could result in additional sales because it would improve the company’s credibility. However, to fulfil a shorter $D$ ⁠, more materials and capacity have to be stored at the main buffer point related to the CODP. If this point is moved downstream, the materials stored here have also undergone more value-adding activities, increasing the value of the stock	✓	✓	✓
	$A_{S, i}$	According to R5, offering some delivery-unique solutions may increase revenue through increased demands and/or the ability to charge premium prices. An increase in potential customisations may nonetheless lead to an increase in item numbers, product range, potential suppliers and time slack, as adding complexity typically adds queue time. This will heighten the need for more planning and control, as well as time slack or mixed flexibility in terms of resources. LuminaireCo responded to this by prioritising delivery-unique orders when it was falling behind. This created disturbances and queue time in production and entailed time and money in terms of planning and control	✓	✓	✓
	$A_{D}$	$D$ determines whether $A_{S}$ has the possibility of being considered $A_{D}$ ⁠. R5 explained, “We are not the cheapest on the market, but we can deliver what the customer wants and within the time they want it”. R7 supported this by claiming their ability to offer delivery-unique products as a vital revenue source. The length of $A_{D}$ determines when customisation can be performed, which should be as late as possible. If customisation occurs later (i.e. further downstream), then the materials and activities specific to such customisation can be respectively acquired and performed later, perhaps based on a particular customer order	✓	✓	✓
AircraftCo	$E_{k}$	If it is assumed that the risk of acquiring materials on speculation decreases closer to $D$ ⁠, then if a supplier is replaced by one that can offer a reduced $E$ so that it falls downstream of the CODP (i.e. within $D$ ⁠), “then, in a way, the whole risk [of purchasing on speculation] will disappear since we [AircraftCo] can buy on customer order” (R8). However, the material cost (i.e. direct material cost) will likely increase		✓	✓
	$I_{k}$	Extending $I$ ⁠, adding time slack to the system can improve machine usage by levelling production. R8 explained, “If we have 10 days to produce something, then we can choose to, for instance, merge some production orders. We can somehow work with sequences in order to increase resource utilisation. But if we only have five days to produce the same things, then this window of opportunity closes […] how we plan the orders, in which sequence. And that should have negative cost implications; cost should go up.” Thus, a longer $I$ would decrease set-up costs but result in larger lot sizes, greater WIP and higher inventory-carrying costs. Under the assumption that quality would remain unchanged or improve, R8 explained that $I$ could also be reduced by outsourcing some part of the production. Although this would result in a higher direct material cost, it would reduce the cost of direct labour and the investments in resources for these value-adding activities. This could be an option if “the supplier has other customers, increasing the efficiency of what they [the suppliers] do, thus gaining economies of scale” (R8)		✓	✓
	$S$	R8 stated, “In some way, $S$ symbolises the critical path, which gives you your planning horizon. The longer this is, the more uncertain it is; the demand over there [in the upstream end of $S$ ] […] for a forecast manager, the critical path, is very important, so how far into the future am I [the forecast manager] acting?”		✓	✓
	$D$	There is a higher risk of carrying out activities upstream of $D$ ⁠, as these are performed based on speculation. This is especially true for companies producing different products and variants. With changes in the mix and volume, the company may produce or buy materials it does not need or even create shortages in the materials it needs. This issue is addressed in the following statement by R8: “If $E$ [upstream of $D$ ] can be reduced so much that it comes inside of $D$ [downstream of $D$ ], then, in a way, the whole risk will disappear since we [companies] can buy on customer order [commitment][…]. If we reduce [ $D$ ] so much that a planning point is moved upstream [of], then it ends up in uncertainty. Then, cost and investment go up”. In many ways, $D$ is an order winner and has significant implications for revenue. Even as an order qualifier, $D$ has potential implications for revenue, such as when $D$ is too long and results in order losses. This point is illustrated in R8’s statement: “If D were to be prolonged, you would most definitely lose business”. A longer $D$ may also indicate that a company needs to compensate customers by offering products at discounted prices. R8 also said, “The forecast becomes more and more reliable [certain] the closer to the CODP you come. If that is the case, then you would profit from a reduced [ $S - D$ segment] […]. Suppose that there are high-volume products where you can work with forecasts based on [demand] history, then the probability of the forecast being better closer to CODP is higher”. If $D$ were prolonged, resulting in a reduced $S - D$ segment, then fewer activities would have to be undertaken based on speculation, leading to reduced risks and decreased buffers (both cycle stocks and safety stocks), which would further reduce the costs of and investments in the buffers	✓	✓	✓
	$A_{S, i}$	By offering some delivery-unique solutions, revenue may increase through increased demands and/or the ability to charge premium prices. In fact, according to R8, if customers are made aware of the potential delivery-unique solution, they may even be willing to accept a longer $D$ to obtain the product they want. “Even though the lead time [ $D$ ] is extended, the revenue might increase because the demand somehow increases because the customers see something they did not know existed” (R8)	✓	✓	✓
	$A_{D}$	R8 did not perceive a correlation between the length of $A_{D}$ and a potential increase in revenue, arguing that a customer is typically not interested in the actual length of $A_{D}$ as long as it is within $D$ ⁠. The planning and control related to the delivery-unique offerings will increase cost and investment		✓	✓
TurbineCo	$E_{k}$	More materials accumulate in the system under the same flow rate because of the longer E and/or the uncertainty in $E$ ⁠, increasing the inventory-carrying cost and investments in them. R12 said that increasing the certainty in $E$ $(σ_{E} \to 0)$ enabled them to better fulfil their internal production plans (⁠ $σ_{I} \to 0$ ⁠) and thus increase the delivery certainty (⁠ $D_{σ} \to 0$ ⁠)		✓	✓
	$I_{k}$	In reducing $I$ enough for the upstream end to be moved downstream of the CODP (i.e. within $D$ ⁠), activities can be aligned to committed customer orders. Less value-added activities will thus be performed on the materials or components stored in the main buffer point located at the CODP. In turn, this will reduce the value and cost of capital at that buffer point. $I$ can be reduced by adding more resources and materials, increasing the production flexibility		✓	✓
	$S$	Prolonging $S$ results in a less responsive system, where more materials accumulate throughout the system. In relation to $D$ ⁠, if $S$ instead can be reduced so that the $S - D$ segment is also reduced, then less activities must be conducted on speculation, also reducing the related risk and cost		✓	✓
	$D$	R12 argued that an increased delivery certainty could result in additional sales because it would improve the company’s credibility. In fact, if an activity performed during $D$ could be minimised or eliminated, rather than reducing $D$ ⁠, the saved time could be used as time slack to increase delivery certainty. To reduce $D$ ⁠, the company may need to increase its flexibility and consequently increase its capacity costs and, in some cases, investments. If the process is less stable, the company may incur higher costs in terms of planning and control, as well as of express transport, to ensure high delivery certainty. In the long run, a higher demand because of a reduced or more reliable (certain) $D$ will require greater capacity, such as machines and employees, resulting in increased costs and investments	✓	✓	✓
	$A_{S, i}$	Shorter $A_{S}$ s enable more delivery-unique offerings to be achieved within $D$ ⁠. Offering these new customisations can increase the market share. If the materials can be purchased on speculation, then shortening $A_{S}$ s can result in more items in stock	✓	✓	✓
	$A_{D}$	R12 explained that if customisation would occur later (i.e. further downstream), then this might give customers less time to change their minds, reducing the complexity of episodes where customers would make changes to open orders. If $A_{D}$ is shorter than $D$ ⁠, then a customer can place an order before deciding on the final customisation. This increased flexibility could be perceived as a service, possibly leading to increased customer satisfaction and more orders	✓	✓	✓

Co	SLT	Data on each SLT's implications for the three absolute measures related to ROI	R	C	In
PumpCo	$E_{k}$	R1 explained that it would be more important that $E$ be stable and predictable rather than short and unpredictable. A predictable $E$ would result in less uncertainty and need for costly safety buffers. However, to increase the certainty in $E$ , the supplier might need to keep a higher inventory or safety capacity on its end, thus increasing cost. R1 also said that increasing the certainty in $E$ ( $σ_{E} \to 0$ ) enabled them to better fulfil their internal production plans $(σ_{I} \to 0)$ and thus increase the delivery certainty $(D_{σ} \to 0)$		✓	✓
	$I_{k}$	Reducing $I$ would most likely result in less buffers and WIP but would increase the need for more flexibility and investments in capacity, in line with the classic trade-off between lead time and capacity. In contrast, increasing $I$ by adding safety time would improve the possibility of levelling production		✓	✓
	$S$	Reducing $S$ might lead to increased uncertainty and disruptions, resulting in more replanning and expediting of orders. Either reducing or prolonging $S$ also has implications for the amounts of materials and resources needed in the supply system to achieve and maintain the length of $S$		✓	✓
	$D$	PumpCo focuses on low volume, delivery-unique products, with more demanding customers. Reducing $D$ has allowed PumpCo to charge premium prices for its products. R1 explained, “We have been able to charge a premium price because our $D$ is shorter than those of our competitors, and we have been more responsive in accommodating our customers” “demand” Still, PumpCo has reached a point where any possibility to earn higher revenue through a reduced $D$ is outweighed by the cost. More capacity and/or material stock should be acquired to reduce $D$ . Additionally, if an activity performed during $D$ could be minimised or eliminated, rather than reducing $D$ , the saved time could be used as time slack to increase delivery certainty	✓	✓	✓
	$A_{S, i}$	An increase in potential delivery-unique variants might lead to an increase in not only market share but also in item numbers, product range, potential suppliers and time slack, as adding complexity typically adds queue time. This would heighten the need for more planning and control, as well as time slack or mixed flexibility in terms of resources	✓	✓	✓
	$A_{D}$	R1 stated that by offering some delivery-unique solutions, PumpCo had succeeded in winning over customers from competitors, as well as being able to charge premium prices. However, PumpCo previously had issues with $A_{S}$ s being longer than D, where customer orders were lost. Moreover, when falling behind on delivery-unique orders, PumpCo responded by prioritising them. This created disturbances and queue time in production and entailed time and money in terms of planning and control. According to R2, PumpCo has now stopped prioritising orders: “We said to ourselves that we shall not go in and prioritise anything; it should be solved by itself. Suddenly, everything flowed, and we managed to reduce queue time.” To maintain $A_{D}$ , PumpCo also invested time and money in designing more stable and flexible processes for activities carried out during $A_{D}$ s	✓	✓	✓
TelecomCo	$E_{k}$	According to R3, a predictable $E$ results in less uncertainty and need for costly safety buffers. Moreover, if one knows the length of $E$ and it is always the same (stable), then they do not need to use a safety buffer at all; they will always get the material at the time they planned for its arrival		✓	✓
	$I_{k}$	$I$ can be prolonged through increased safety lead time, resulting in not only greater flexibility but also more materials accumulating. In contrast, increasing capacity makes it possible to reduce $I$ and the amount of materials accumulating		✓	✓
	$S$	Prolonging $S$ results in a system that is less responsive to changes in products or technology, where more materials and investment accumulate in the system. Prolonging $S$ , where $D$ is unchanged, also results in a longer $S - D$ segment and more uncertainty where more activities must be conducted on speculation		✓	✓
	$D$	If an activity performed during $D$ could be minimised or eliminated, then rather than reducing $D$ , the saved time could be used as time slack to increase delivery certainty. Still, R3 and R4 recognised key motives for reducing $D$ and potentially increasing the market share. However, they did not see the possibility of increasing the selling price due to their highly competitive market	✓	✓	✓
	$A_{S, i}$	Only the $A_{S}$ s that are at or downstream of the upstream end of $D$ can be used for delivery-unique offerings and possibly increase the market share. However, creating these variants will result in more item numbers and possibly increase both the volume and the mix of items in stock	✓	✓	✓
	$A_{D}$	$A_{D}$ has obvious potential for enhancing a company's ability to generate revenue. However, the complexity of planning and controlling these orders increases with more delivery-unique offerings	✓	✓	✓
LuminaireCo	$E_{k}$	Prolonging $E$ would result in an increase in raw material inventory. In contrast, in reducing $E$ , LuminaireCo might have to use faster and more expensive transportation modes and/or increase the cost of direct materials by purchasing more from local suppliers. Even so, R6 believed that an increased certainty in $E$ “could result in additional sales because we [LuminaireCo] are able to keep what we have promised [promised due date]” R5 said that increasing the certainty in $E$ $(σ_{E} \to 0)$ enabled them to better fulfil their internal production plans $(σ_{I} \to 0)$ and thus increase the delivery certainty $(D_{σ} \to 0)$ . Moreover, if $E$ could be reduced so that it would fall within $D$ , then less materials would need to be purchased on speculation, reducing the risk of being out of stock, as well as buying wrong items in terms of the demand		✓	✓
	$I_{k}$	Reducing $I$ would most likely result in less buffers and WIP but would increase the need for more flexibility and investments in capacity, in line with the classic trade-off between lead time and capacity		✓	✓
	$S$	Prolonging $S$ results in a system that is less responsive to changes in products or technology and where more materials and investment accumulate in the system. For instance, LuminaireCo is undergoing a technology transition; traditional light sources are being replaced with light-emitting diode technology. According to R5, they “have over 80 generational changes this year”, and these changes have resulted in reengineering products, sourcing new items and phasing out outdated ones. R6 provided an example: “We are acquiring things [components] now in February, and it is not until August/September that the change will take place according to plan. But in case this does not go down as planned, we might have to postpone the change until October/November […]. We also retrofit the demand by using campaigns, when we are too late with the generational change and need to get rid of components and products. Not having enough or the right materials in stock may also result in loss of sales, where customers are unwilling to wait for the products to be produced. Still, this is an indirect implication, where $D$ could not be fulfilled		✓	✓
	$D$	Reducing $D$ has obvious and strong implications for a company's ability to generate more customer orders, especially if $D$ is an order winner. R5 even said, “We get more customers because we have short lead times [ $D$ ], or we can reduce our $D$ even more, which our competitors can't” In contrast, not fulfilling $D$ would most likely result in loss of sales. Moreover, R6 argued that an increased delivery certainty could result in additional sales because it would improve the company’s credibility. However, to fulfil a shorter $D$ , more materials and capacity have to be stored at the main buffer point related to the CODP. If this point is moved downstream, the materials stored here have also undergone more value-adding activities, increasing the value of the stock	✓	✓	✓
	$A_{S, i}$	According to R5, offering some delivery-unique solutions may increase revenue through increased demands and/or the ability to charge premium prices. An increase in potential customisations may nonetheless lead to an increase in item numbers, product range, potential suppliers and time slack, as adding complexity typically adds queue time. This will heighten the need for more planning and control, as well as time slack or mixed flexibility in terms of resources. LuminaireCo responded to this by prioritising delivery-unique orders when it was falling behind. This created disturbances and queue time in production and entailed time and money in terms of planning and control	✓	✓	✓
	$A_{D}$	$D$ determines whether $A_{S}$ has the possibility of being considered $A_{D}$ . R5 explained, “We are not the cheapest on the market, but we can deliver what the customer wants and within the time they want it”. R7 supported this by claiming their ability to offer delivery-unique products as a vital revenue source. The length of $A_{D}$ determines when customisation can be performed, which should be as late as possible. If customisation occurs later (i.e. further downstream), then the materials and activities specific to such customisation can be respectively acquired and performed later, perhaps based on a particular customer order	✓	✓	✓
AircraftCo	$E_{k}$	If it is assumed that the risk of acquiring materials on speculation decreases closer to $D$ , then if a supplier is replaced by one that can offer a reduced $E$ so that it falls downstream of the CODP (i.e. within $D$ ), “then, in a way, the whole risk [of purchasing on speculation] will disappear since we [AircraftCo] can buy on customer order” (R8). However, the material cost (i.e. direct material cost) will likely increase		✓	✓
	$I_{k}$	Extending $I$ , adding time slack to the system can improve machine usage by levelling production. R8 explained, “If we have 10 days to produce something, then we can choose to, for instance, merge some production orders. We can somehow work with sequences in order to increase resource utilisation. But if we only have five days to produce the same things, then this window of opportunity closes […] how we plan the orders, in which sequence. And that should have negative cost implications; cost should go up.” Thus, a longer $I$ would decrease set-up costs but result in larger lot sizes, greater WIP and higher inventory-carrying costs. Under the assumption that quality would remain unchanged or improve, R8 explained that $I$ could also be reduced by outsourcing some part of the production. Although this would result in a higher direct material cost, it would reduce the cost of direct labour and the investments in resources for these value-adding activities. This could be an option if “the supplier has other customers, increasing the efficiency of what they [the suppliers] do, thus gaining economies of scale” (R8)		✓	✓
	$S$	R8 stated, “In some way, $S$ symbolises the critical path, which gives you your planning horizon. The longer this is, the more uncertain it is; the demand over there [in the upstream end of $S$ ] […] for a forecast manager, the critical path, is very important, so how far into the future am I [the forecast manager] acting?”		✓	✓
	$D$	There is a higher risk of carrying out activities upstream of $D$ , as these are performed based on speculation. This is especially true for companies producing different products and variants. With changes in the mix and volume, the company may produce or buy materials it does not need or even create shortages in the materials it needs. This issue is addressed in the following statement by R8: “If $E$ [upstream of $D$ ] can be reduced so much that it comes inside of $D$ [downstream of $D$ ], then, in a way, the whole risk will disappear since we [companies] can buy on customer order [commitment][…]. If we reduce [ $D$ ] so much that a planning point is moved upstream [of], then it ends up in uncertainty. Then, cost and investment go up”. In many ways, $D$ is an order winner and has significant implications for revenue. Even as an order qualifier, $D$ has potential implications for revenue, such as when $D$ is too long and results in order losses. This point is illustrated in R8’s statement: “If D were to be prolonged, you would most definitely lose business”. A longer $D$ may also indicate that a company needs to compensate customers by offering products at discounted prices. R8 also said, “The forecast becomes more and more reliable [certain] the closer to the CODP you come. If that is the case, then you would profit from a reduced [ $S - D$ segment] […]. Suppose that there are high-volume products where you can work with forecasts based on [demand] history, then the probability of the forecast being better closer to CODP is higher”. If $D$ were prolonged, resulting in a reduced $S - D$ segment, then fewer activities would have to be undertaken based on speculation, leading to reduced risks and decreased buffers (both cycle stocks and safety stocks), which would further reduce the costs of and investments in the buffers	✓	✓	✓
	$A_{S, i}$	By offering some delivery-unique solutions, revenue may increase through increased demands and/or the ability to charge premium prices. In fact, according to R8, if customers are made aware of the potential delivery-unique solution, they may even be willing to accept a longer $D$ to obtain the product they want. “Even though the lead time [ $D$ ] is extended, the revenue might increase because the demand somehow increases because the customers see something they did not know existed” (R8)	✓	✓	✓
	$A_{D}$	R8 did not perceive a correlation between the length of $A_{D}$ and a potential increase in revenue, arguing that a customer is typically not interested in the actual length of $A_{D}$ as long as it is within $D$ . The planning and control related to the delivery-unique offerings will increase cost and investment		✓	✓
TurbineCo	$E_{k}$	More materials accumulate in the system under the same flow rate because of the longer E and/or the uncertainty in $E$ , increasing the inventory-carrying cost and investments in them. R12 said that increasing the certainty in $E$ $(σ_{E} \to 0)$ enabled them to better fulfil their internal production plans ( $σ_{I} \to 0$ ) and thus increase the delivery certainty ( $D_{σ} \to 0$ )		✓	✓
	$I_{k}$	In reducing $I$ enough for the upstream end to be moved downstream of the CODP (i.e. within $D$ ), activities can be aligned to committed customer orders. Less value-added activities will thus be performed on the materials or components stored in the main buffer point located at the CODP. In turn, this will reduce the value and cost of capital at that buffer point. $I$ can be reduced by adding more resources and materials, increasing the production flexibility		✓	✓
	$S$	Prolonging $S$ results in a less responsive system, where more materials accumulate throughout the system. In relation to $D$ , if $S$ instead can be reduced so that the $S - D$ segment is also reduced, then less activities must be conducted on speculation, also reducing the related risk and cost		✓	✓
	$D$	R12 argued that an increased delivery certainty could result in additional sales because it would improve the company’s credibility. In fact, if an activity performed during $D$ could be minimised or eliminated, rather than reducing $D$ , the saved time could be used as time slack to increase delivery certainty. To reduce $D$ , the company may need to increase its flexibility and consequently increase its capacity costs and, in some cases, investments. If the process is less stable, the company may incur higher costs in terms of planning and control, as well as of express transport, to ensure high delivery certainty. In the long run, a higher demand because of a reduced or more reliable (certain) $D$ will require greater capacity, such as machines and employees, resulting in increased costs and investments	✓	✓	✓
	$A_{S, i}$	Shorter $A_{S}$ s enable more delivery-unique offerings to be achieved within $D$ . Offering these new customisations can increase the market share. If the materials can be purchased on speculation, then shortening $A_{S}$ s can result in more items in stock	✓	✓	✓
	$A_{D}$	R12 explained that if customisation would occur later (i.e. further downstream), then this might give customers less time to change their minds, reducing the complexity of episodes where customers would make changes to open orders. If $A_{D}$ is shorter than $D$ , then a customer can place an order before deciding on the final customisation. This increased flexibility could be perceived as a service, possibly leading to increased customer satisfaction and more orders	✓	✓	✓

Note(s): C = cost, Co. = company, In. = investment, R = revenue

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