You know, there really isn't a "one size fits all"- especially when it comes to babies and feeding. My daughter was having rice cereal in two bottles a day when she was 4 weeks old, and then was actually being spoon fed rice cereal at 2 months old. My son on the other hand didn't actually start with rice cereal in his bottle until he was about 8 weeks old. And many moms absolutely won't do this because of the information out there about just when you are supposed to put babies on solids.
Babies don't usually over eat. They instinctively stop eating when they are full. I would venture to say that if your little one is ok as far as his weight and is not overweight, then he is ok.
Some babies burn those calories faster because of higher metabolisms or whatever so they require more frequent feedings. My daughter was one of those babies. She had a huge appetite but was never overweight. My son- not such a big eater but was not underweight.