That sounds in line with what my wee yin was taking in back then.
Mines doing the exact same thing - hes four weeks on Monday and usually drinks between 50-120 x
My nearly 4 week old is on 5oz
My 5 week old is on 3 oz every 3 hours x
4 week old on 4oz every 3 hours
My little boy was on 4-5oz he’s now 5weeks and on a solid 5oz