R12 OM Restrict Actual Departure Date to System Date

Hello,

We are on 12.1.3 and using Oracle Order Management and all financial modules. While doing ship confirm  and confirm delivery, actual departure date is required to be mentioned . This is the date on which inventory gets hit. In our case it is observed that when the user puts actual departure date of a back date, it creates issues.

E.g  There is a stock of  Quantity 10 for an item as on date(sys date). For the same item and for the same inventory order is booked. The person by mistake enters the date of actual departure as 15 Dec,14 on which date there is no stock available. Now there is an in-transit receipt of the same item on 20th December for Quantity 10.   when the cost manager runs , it is observed that the entry for receipt has hit Average cost variance instead of Inventory.