The results from the order allocation run (ARun) impact the availability of stock during the availability check. Hence, the availability check considers the quantities that are already reserved by the order allocation run for requirements and stock/receipts.
You have created an article that is relevant for order allocation run
You have executed the order allocation run for the article
During the availability check, 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 does not consider them as available quantity during the availability check. Therefore, availability check can promise only the remaining stock for any future requirements.
Assume the following:
Oct. 9, 2013: Batch stock of 100 pieces
Oct. 16, 2013: Purchase order for 100 pieces
Nov. 3, 2013: Sales order (4711) for 100 pieces
Nov. 10, 2013: Sales order (4712) for 150 pieces
Order allocation run allocates the available batch stock to sales order #4712.
Result from Order Allocation Run
During the availability check for a new requirement (sales order #4711 requires 150 pieces), as the batch stock is already allocated to a requirement, the system only proposes the remaining quantity of stock or future receipts and requirement as the ATP quantity. That is, the availability check promises the purchase order of quantity 100 pieces and the remaining 50 pieces will be delivered later.
Results from Availability Check