Baby lost 8% of birth weight at 4 days old.

Is this average, or on the higher side? I feel like my milk has come in.. and I’m feeding on demand. I haven’t been the best at tracking times because i feel when I do the time goes by slower for me and drags but he’s feeding anywhere from 10-20minutes on each side for each feed... please help with constructive criticism. I’m not going back to work so I don’t want to pump and get an oversupply of milk.

Thank you in advance..