Formula fed babies

How much formula? My baby had his 4 month check up. He is 24 in long & 16 lbs 5 oz. dr asked how much does he eat and he assumed 3-4 oz I said no 5-6 sometimes 7. He looked shocked and said how often I said 3-4 hours sometimes longer stretches. I thought my baby was right on track with his amount since he doesn’t show signs of over feeding he’s not spitting up or anything. He didn’t seem concerned with his weight either so I was just confused on to why he looked so shocked but he said 3-4 hours+ was fine.