Every baby is different and if it works, go with it

If it works to go to 4-1/2 hrs when he naps longer, that's perfectly ok. Consider yourself blessed to have such nice naps

:wink:
For us, Zoe (10 months) can go 3-4 hrs in between activity now. But we are pretty much on a 3 meal schedule like us. Though, I think on average that is a little earlier than the "norm".
Wake at 7
Breakfast at 8
Nap usually 45 minutes (9:15-9:45)
Lunch at 11-11:30
Nap 1-3/3:30
Snack
Dinner at 5:30
Bottle at 6:30
Bed at 7