Hi Jason
Didn't work after adding the option for the first product(so plus $50) when adding the second item of the same product to the cart it deducted the $50 from the first as well.
I tried this idea you talk about here:
showthread.php?t=25444 but couldn't get it to work either . My options are 4 inch extra $50 or 7 inch no additional charge.
Thanks for your help