BUG: Period Selector Position, Above the table, not updating the price at paypal

Pro Sites 3.5.1
When configured: Pro Sites> Pricing Table> Period Selector Position> Above the table (Enable Pricing Table: Checked)
I've one level with three payment periods (monthly, quarterly yearly). If the user select the a period type (i.e yearly ) then click "Chose plan" then click paypal button it will be redirected to paypal with monthly price.
-It works fine: if the user chose the plan then click paypal button directly without clicking "choose plan" (it seems this button is resetting the values)
-It works fine: if configured as: Pricing Table> Period Selector Position> First column (Part of table)
I think the bug found at: \pro-sites\pro-sites-files\js\checkout.js (but I don't know how to fix it)

I cannot provide access, so please confirm if it is a bug or not and how to fix it?

Super thanks,