agoricki, I have not tried to do what you want, but if I were to try, I would use a Table. In that table you can insert multiply items and set a formula for each. This may accomplish what you a looking for. Another way in is to insert Items directly into the assembly and and choose the item that corresponds to your quantity takeoff (each item having a different production rate-this is what is happening with the .80). You can use an 'If' statement in the Assembly formula to display item options based on quantity input. I believe it is possible, you may have to think geometrically.