There are 2 flareon with trump card. One of the trump cards on a flareon has 5pp. The other trump card on flareon has 8pp. The moves both have 1pp left. Would Flareon #1(with 5pp trump card) have more power or Flareon #2(with 8pp trump card)? They both have 1pp left
Its calculated based on remaining pp, not percentage left or whatever, so they would do the same amount of damage, 200bp.
Take a look. The power only increases below 5. It won't increase if it loses more PP, it's after PP drops to a certain level.