If he's content and growing well, he's getting all he needs. I think sometimes these 'recommendations' especially when they come from formula manufacturers are just designed to get you to overfeed and use more formula than you need to (so they make more money!). At 12 weeks, I was just switching from BF, and my daughter was probably only having about 3-4 oz 6-7 times a day. Even now (she's 6 months and not really taking in any solids at all yet), she only eats about 5 oz some feeds, though sometimes 7 oz, with 5 feeds a day. That's a lot less than she 'should' be eating. But she's jumped from 25th to 65th centile even though she doesn't eat much and is very healthy and ahead developmentally. So don't worry about it. Your baby is the best judge of how much he needs to eat. Just feed on demand and don't worry about the numbers too much.