Re: I don't want to undo what progress we've made, but. . .
Does he pee when you put him on the potty after he goes to bed? If he does most of the time, I would say he actually has to potty. If he doesn't then he is absolutely trying to stretch it out. Maybe switch up the routine? After the bottle, maybe read a story and then offer the potty.
Loving wife to my gaming, sports loving hubbie. Sahm to J 2/12 and L 10/13