Evolved fighters still gain the amount of skill point(s) of their original tier when levelling up through fights. But they gain the amount of SP of their new tier when levelled up via the power up feature in collections where you sacrifice other fighters.
For example: a bronze Eliza evolved to gold will only get +1 SP after levelling up from fights. But she will gain +5 SP after levelling up from Power Up.
For example: a bronze Eliza evolved to gold will only get +1 SP after levelling up from fights. But she will gain +5 SP after levelling up from Power Up.