"Prorate value of donation when upgrading" ?

I have a scenario where users will be jumping from one plan to another, and I understand there are upgrade options that allow for prorating when switching plans and having them do this on their own, however, I would like to be able to do this manually on a case-by-case, so I'll be utilizing the donation feature to compensate for payments.

I don't understand what the setting "Prorate value of donation when upgrading" does (if it's a donation, what are they upgrading to?). I looked in the manual and couldn't find it. Can you please define what this does and a use-case?

Thanks.

I don't understand what the setting "Prorate value of donation when upgrading" does (if it's a donation, what are they upgrading to?). I looked in the manual and couldn't find it. Can you please define what this does and a use-case?

It discounts their next purchase based off their donation amount. So for example they donate $5 and your plan is $10 they now only pay $5 due to the donation prorating.

You shouldn't need this though for what you described you're trying to do. CBSubs Promotions would help best with what you're wanting to do still.