Well, I'd keep an eye on it. It still sounds a bit developmental, but I think if he continues to get broken naps, he could use a little push in A time. 45min is generally UT, which I'm sure you know, but it can be OT for some (but it doesn't seem like his are OT). I would be careful with that last A to bed if he continues to do a shorter nap in the pm, as that can lead to OT nights. I wouldn't do over 3hr, if possible.