MRP and Inventory Reservations MD04
I have been digging on inventory reservations and have found nothing to indicate the the MRP element OrdRes is "decremented" by partial issues of inventory on process orders PI01 type. Were seeing the required quantity stay the same until final issue flag is set (or entire reserved qty issued) and final confirmation/clear reservations set on COR6N. Is this standard SAP functionality or is there configuration I've missed somewhere?
The order reservation quantity does not change based on the goods Issue, but you can see withdraw quantity updated in RESB table. I feel the problem you are encountring is that you are making Unplanned-GI against the order, in that case the withdraw quantity does not get updated.
Please let us know how you are performing the goods Issue. General mistake endusers could be doing is that in transaction MB1A, the user may be entering the process order details in the Goods Issue: Overview screen(2nd-Screen) instead of using the GI--->Against Order/Reservation option in the intial screen.
Please go through this link [Discussion on Unplanned GI|http://www.sapfans.com/forums/viewtopic.php?f=9&t=258256&p=777417]