Possible bug with condition-based moves.

[Skyfabric]

I'm not sure how far this extends, but I can confirm it with Assurance. Payback, I'm not so sure of, but the gist of it is this.

 

When selecting a move that has a criteria that affects the power of said move, there seems to be a discrepancy.

-In the case of Assurance, taking damage prior to usage of the move does not increase the power from 60 to 120.

-In the case of Payback, moving before or after the opposing pokemon does not seem to affect the power (where it should raise from 50 to 100)

 

There are a handful of other moves that function similarly to these two, such as Facade. I do not have the resources as of yet to test these, but it's something to look into.