If Oda was going to end act 3, it would have been right after chapter 1000, when we saw all the Scabbards on the floor defeated, Luffy getting the first hit in Kaido and they preparing to start the fight. But Oda chose to start the fight, not just this one, but all the other ones in the castle, Act 3 is not going to end. I could be wrong, but it just doesn't make sense to me to stop act 3 right now.