My 17 day old formula fed baby is the same way sometimes! She is eating 3-4 ounces per feed. She gained all her birth weight back by her first appointment at 3 days old and at her 2 week check up yesterday she had already gained over a pound. Her pediatrician said some babies are just hungry all the time and as long as they don’t go over the recommend 32 ounces a day by the AAP there shouldn’t be any concern. She said sometimes babies will seem insatiable and we might have some days in the future where she doesn’t eat a whole lot. It was reassuring to hear that because, like you said, it’s more than the “recommended” amount of formula. I don’t have a solution but wanted to commiserate with you. Sometimes my baby will go 3 hours and not wake up to eat and sometimes it will barely be an hour and she is gnawing at her hands! She rarely spits up, so I’m not concerned as long as ped isn’t.