Questions on Rules-Based ATP and Purchase Requisitions for STOs

Question

Hello experts,
We are working on rules-based ATP configuration and have several questions about the functionality.  Iu2019m hoping that some of you are using this functionality and can help give us direction.
In our environment we have multiple distribution centers and multiple manufacturing plants.  We want to confirm sales orders against stock and production orders in any of those plants, depending on the locations that have stock or planned production.  For example, we will place a sales order against plant A.  If there is not enough stock in plant A then rules-based ATP will use location determination to check in plant B, then C.  The scope of check on the ATP check will include stock and released production orders.  We will configure plant A as the u201Cconsolidation locationu201D so if stock is found in plants B or C then stock transport orders will automatically be created to move the stock to plant A before shipping to the customer.
We have configured rules-based ATP and this functionality is working well in our Development system.  The ATP check is executed and uses the rules-based ATP to find eligible stock in other plants.  The system is also creating purchase requisitions to move the stock to the consolidation plant. 
Our first concern is that there doesnu2019t appear to be any firm linkage between the sales order and the resulting purchase requisition.  For example, if we create sales order 123 for plant A and the rules-based ATP finds stock in plant B it automatically creates a purchase requisition 987 to move the stock from plant B to plant A.  However, there doesnu2019t appear to be a linkage between sales order 123 and purchase requisition 987.  For instance, if we delete sales order 123 the purchase requisition doesnu2019t get deleted. 
Our second concern is that the quantity on the purchase requisition can still be confirmed against later sales orders.  For example, say the above scenario resulted in a purchase requisition 987 that consumed all the stock available in plant B.  We then create a second sales order 456 for the same product.  Plant A is out of stock so the rules-based ATP looks in plant B.  We would expect that plant B would also not have any stock because itu2019s all been consumed by the purchase requisition.  Instead, the system creates a second purchase requisition to move quantity from plant B to plant A.  Itu2019s as if the system doesnu2019t realize that the purchase requisition 987 is already planning to move stock out of plant B.
Does anyone have any thoughts or suggestions on these two scenarios?  Is there a way to configure the system so there is a hard linkage between the sales order and the purchase requisition so that if the sales order is deleted then the purchase requisition is also deleted?  Should ATP realize that purchase orders are consuming inventory and not allow later sales orders to confirm against that same inventory?  Any advice or experience would be greatly appreciated.
Thanks,
David Eady
Application Delivery Team Lead
Propex, Inc.

Answer 1

Hi,
The scheduling is done in SCM, and from there, whenever the RBA is triggered, the calculation is done always with the old route in SCM. Until you get back to R/3 this is when your route is determined. But the ATP check is always with the original route. So the idea would be that you change the values of the route while still in APO, this is possible via the user exit. Should be done in scheduling in APO.  
Hope this information is helpful.
Regards,
Tibor