Control cells

I'm not certain how to even ask this question. That frustrates me because I have the 2007 excel bible but I've had no luck looking it up.

The attached worksheet shows a simplified parts pick sheet for a warehouse. Based on Employee and selected options it tells the warehouse how much of a certain item to pack for an employee. There is a calculator based on simple IF, THEN, ELSE type of logic.

There is a text box on the sample file that clarifies the behavior of the calculator I am trying to control.

And, if this is something that is really long, involved, and a pain ... cool. I will happily take advice that points me in a general direction. Many thanks guys.

Let us know if you have any questions.

Question: Can I buy you a beer? Your solution will work nicely. And, since I have never worked Data Validation before it gives me a new study subject to see what else I've missed out on. Thanks.