My baby boy is now 3 months old (corrected), 12 lbs and still taking 140ml /4 hrs. (Abbott Similac NeoSure which is specially for pre-mature n low weight baby). I think your baby is quite good if he can take 120ml / 3 hrs. Don't worry about the night feeding problem, he will refuse to drink while he really want to sleep then you can skip feeding him at midnight.