Depends on what gains you think he had after spirit room.Goku just stated he was at a whole other
level.But,considering how much more powerful Humans Cell/Sixteen are than Kamiccolo/Seventeen,
Kamiccolo could still be weaker than them after his training and still have become strong enough to
be considered of another level compared to his previous strength.
At Buu Saga,i don't think he's too different compared to 7 years before.
All in all,there's a good chance he stops at 4.