Item Cost & stock valuation

We discovered a little bit of a trap for new players.  I accept some of the blame.

We deal mainly with 2-3 trusted suppliers buying a wide variety of stock items.  Sometime we will place an order for 10 items of which we know 8 of the prices and we will send the PO with 8 prices and 2 items at $0.  The supplier will invoice us the correct $ from their price list.

What we have been doing is:

1. Place order
2. Inventory Receipt the goods with those two items still showing $0 on the PO
3. Bill the Inventory receipt and update the prices.

The experienced people on this forum will now see the problem.  This process at No 2. means that the two unpriced items will go into inventory valued at $0.  The $ attributed to their cost when we enter the Bill will post to Inventory Variance account.