I'm creating an order form with several dropdown lists.  One of the lists has shirt sizes in it for XS, S, M, L, XL, 2XL and 4XL.  I have created values on the binding tab for 2XL and 4XL which increases the prices by $2.00 for 2XL and $4.00 for 4XL.  My unit price and my total price calculate great...