My understanding is the mezzanine is closed for all basketball. If the lower arena sells out it sells out. It will be interesting if we're having a good season. Do they fold to pressure for big games or keep it closed to drive ticket demand.
It looks more or less like most other arenas with basketball in that the seats that extend to the court are pulled back for a concert leaving the “sunken” feeling. Not unusual in my experience and won’t exist when set up for a game.