This was a worry for me when mine were that small and I asked their doctor how would I know when to bump them up.....I feed them every 3 hrs.... She said when they start getting fussy and it's like an hour before a feeding and multiple times it happens they need more..... Sometimes it's like one or 2 finds a day they would need bumped up or they didn't finish a bottle.

My son is still at 4 oz at 6 months so if your child is not crying or cranky sfter 4 oz thsts enough

My husband fed him earlier last night but then I was told that when he sucks his hands, that's a sign of hunger too

Does he seem content at 4oz or are noticing that you have to feed him sooner than normal?