J.C.
I agree that each child is different, as long as your child is full, the amount is fine. If you are worried that it may be to little, check to make sure he isn't gulping down the formula. Also, my pediatrician said that formula fills the baby up for longer then breast milk, so that could be why it is every 3-4 hours. I breastfed my daughter, so it was about every 2 hours for me. When we switched to formula she could go longer between feedings. We started out filling up the bottle to 6 ounces and letting her decide when she was full. When we figured out how much she liked to eat at a time we cut back the waste.