Product Options - Codes not changing

I have upgraded to 2.0.5 from 1.3.5.

It appears that my product options did transfer, however they are not functioning in the same way as they did with 1.3.5.

I have product with a radiogroup and a checkbox set of options.

When I select a radiogroup option the product code does NOT change.

When I select the checkbox option the product code does change. And as long as the checkbox is checked selecting different radiogroup options does change the product code.

NOTE that the price does change properly regardless of the option selected.

Any one else have the problem? or better yet offer me a solution??