My son is 7wk old at 5wk old i had to put him on hungrier formula but hes demanding less than 3hr feeds at every 2hrs and has 6-7oz why is this?

Add up total: You need to add up what he is taking in 24 hour period. He should be consuming 32-36 ounces in that time, absolute max 40 ounces if he is not spitting up ANY of the formula. That is enough calories. He may want to just have some sucking time.You don't need to feed him every time he makes noise - there can be other reasons for him to make noise. He may also be getting ready to start sleeping nights

Unique babies: Each child is different and as a general rule it is best to feed young infants on demand. As long as baby is showing cues of hunger and does not seem to have excessive spitting up, it is ok to feed her/him. Depending on if baby is primarily breastfed, he/she may not be getting as much as you think. Your physician will check baby's weight and make any necessary changes.