The results from order allocation run (ARun) impact the net-requirement calculation during MRP run. Hence, MRP considers the quantities reserved by order allocation run for requirements and stock or receipts.
You have created an article that is relevant for order allocation run
You have executed the order allocation run
During the planning run, the system checks for the stock or future receipts that are already allocated to the requirements during the order allocation run. Since the available stock or future receipts and requirements are already allocated, the system cannot consume them during the MRP run. Therefore, the system proposes a new procurement proposal for the requirements.
Assume the following:
Oct 9, 2013: Batch stock of 50 pieces
Oct 16, 2013: Purchase order for 50 pieces
Nov. 3, 2013: Sales order (4711) for 100 pieces
Nov. 10, 2013: Sales order (4712) for 100 pieces
Order allocation run allocates the available batch stock and the purchase order to sales order #4712.
MRP result
During the MRP run, the system proposes a new proposal, for example purchase requisition, for sales order #4711 dated Nov. 3, 2013.
Quantities reserved by Order Allocation Run is considered during MRP
Note
For an article that is not relevant for order allocation run or if the order allocation run is not executed, MRP always procures at the latest date, and may even fail to fulfill the requirements in certain cases.