Order Entry Available is incorrect

I have seen this problem since V6 and now we're on V8.03407C.

When entering a line item for a sales order, the top right of the screen says on-hand = 0, available = 1,000! Not even close. I am aware of the conversion program to correct these values but that does not help during day to day operations.

Has anybody been able to customize the order entry detail screen to accurately display available inventory? Can a custom field perform a calculation as in "OnHand Minus SalesAllocated Minus JobAllocated"? This is important to us because many of the parts we use in assembly are also sold as components.

Thanks in advance.

Randy Weber