What's between PO reserved qty and missing parts?
I make a test but now confused about the result for my sap, so I want somebody can help me to clarify the steps listed as below, if wrong please point it out and tell me which result should be right
1.after production order(PO) created then reserved qty(2pcs) created, the qty(2pcs) keeps same when I released this order, and missing parts list created if unrestricted stock(1pcs) can't meet the demand(2pcs)in this order. then if I receive parts(2pcs) to our stock, means unrestricted stock(2+1=3pcs) raised, if it can meet the demand of this order, then missing parts list disappeared no matter this order is only opened or had been released ,the same result happened.
2.then I opened next two orders, but I find same missing parts list occurred in this two orders and show required qty is 2pcs and committed qty is 1pc (this 1pc I think is our stock 3pcs deduct the first order demand 1pc),it seems system doesn't conside the required date of this two orders. I think it should be the early one should show required qty is 2 and committed qty is 1 ,and the later one should show required qty is 2 and committed qty is 0( because no available qty left)
3. if I change the finish date of one order to early or later ,I find the missing parts keeps same, that means system doesn't recalculate the demand and stock for this order again
4. if I increase the unrestricted stock enough, then missing parts list disappeared step by step following the original require date of orders, it is not effected by it's current required date (this date I can change)
From above these result, I want to know what's the correct result or what should be it looks like.
1. Is it the same result that order opened or released for missing parts list?
2. The required date changed; does the missing parts list keep same or changed accordingly? Later if stock raised then which order has the higher priority to get parts, which rule they should obey, the original require date or the new required date?
3. If I change the required date, how can I free the reserved qty except the technically completed applied?
4.if these also influenced by which background configuration , also please explain it.
Any advices are welcome!