Dear T W
In standard system SAP behave differently for Sale order and credit/debit memo requests. I had once faced the same problem in my previous company and I got solution in my this thread.
http://scn.sap.com/thread/1959629
I just followed the same and I was able to control this.l So I made a new reason for rejection for credit/debit memo requests and asked accounting guys to put this reason for rejection.
Now for your other query why system is behaving like this is a question mark for me also. I think system behaves differently because in sale order we make deliveries but in credit/debit memo requests we only create billing so system is not considering status until we tell system that this reason for rejection is not relevant for billing.
I know this is not a valid reason and may be sounds stupid but I have no other reason to give you here. Hope you can share some better idea. Image may be NSFW.
Clik here to view.
Thank$
