What version(s) are you testing in?

Also I may have 1 bug to work out on that add_product as I am getting on some versions the debug log message that could be due to customizations I am working on or an actually issue with this add-on and my code change ...

But let me know what you run into ...

My tests are based on the Download Products in the Demo data for:
/index.php?main_page=product_info&cPath=54_60&products_id=133
/index.php?main_page=product_info&cPath=54_60&products_id=179