1) What are you using as a "unique identifier"?
2) Are CostID1 and CostID2 separate fields??? (I hope not)
Sometimes it is possible to define an expression that uses data from the product record and the specified quantity and calculates the cost. This can be a different expression for each product if you store it in a text field in the products field and use the evaluate function to compute the cost for your production run.
CostID is the unique identifier for each separate cost, and ProductID ties it back to the specific product.
CostID1 and CostID2 are separate records in the Costing Table.
Phil, I see where your going with that idea, and I like the concept. I would need to determine if there was a constant value that I could use??? Hmmmm.... Food for thought