Yes so, to make it totally clear, this is how powerup is supposed to work:
You discard as many pairs/triples/quads as you want.
Then, you get as many aces as you are entitled to (including aces earned from chain combos (but not aces from Jokers, which are fetched immediately)).
Then powerup phase is over.
In the online version, it is instead coded that you discard your pairs/triples/quads and then immediately fetch the aces for each, which has been ruled as incorrect.
This whole issue came to light because of EX characters powerup scamming, as mentioned earlier, where Sirlin mentioned that the online rules were incorrect.