Something about that SIU's last sentence - "More bangs doesn't always equate more power."
Maybe Chang is more pwerful than Viole, but can control only 2 or 3 rooms, or maybe Quatro isn't defeated yet.
I somehow can't see Chang being stronger than Viole (Viole put a scratch on Urek after all while protecting Miseng), but it could be a good fight and a fair bit closer than might be expected.
About Quatro, I'm just saying it's possible. If Baam has a method of recovering from injuries, there are bound to be others too. Although I hope that lobster is not something common or accesible to people like Quatro.