Price not updating in config options cart

Im creating a custom order form template based on "modern" template.
However the price in config options is not updating when switching billing cycle check box.
It's updating in the ajax cart though.

Is this a known bug with modern template?

I tried to replace the billing cycle check box by the dropdown list from "cart" template but I faild (keep getting errors). Is anyone managing to basically get the "modern" template but with dropdown list for the billing cycle ?

Any help will be apreciated.