Over/Excess consumption in Production Order through picking list journal


I am using AX 2009 version, I am facing one problem in production orders. In the production orders raw material consumption ie picking list journal is over consumping as compare to RAF quantity. For EX. Production order with 1000 qty and bom contains item A = 1000, item B= 2000, item C=1000. But unknowingly over or excess qty is getting posted for that resperctive production order. End user posting item A=1500 instead of 1000, item B=3000 instead of 2000, item C= 2000 instead of 1000 i.e. over / extra consumption where as RAF is with 1000 qty. This is creating problem for raw material stock and consumption pattern. I can’t restrict this but I want to highlight this qty before production RAF all qty. I want to display message box with Yes/No option to inform that henceforth picking list journal qty is getting excess by respective qty. Is this correct way coz I will put this code while posting picking list journal itself. Or any body is having any other idea? Need help.