Should I limit my son's formula intake?

2.5 is just an estimate. My daughter is 5 months old, 14lbs 9oz and only takes 24-26oz a day....10oz less then she should be taking if I followed that rule. Every baby is different and will take what they want and gain what they need to. My daughter puts on 4oz a week. Has since birth. Some babies put on over a pound a week. It just depends on the baby.