Amount of pumped milk for 3 month old?

I’m going back to work in about 3 weeks and my son will be 3 months old at that point. I asked his pediatrician how much pumped breastmilk he should have per session (typically about 2 hours apart for breastfeeding) and she said 4-6 oz. I feel like that’s a lot and that I previously read more like 2-3 oz but I’m not certain. I think that might’ve been from La Leche but I’m having trouble with their website so thought I’d ask here.

I love his pediatrician, she’s great and very knowledgeable, but I think breastfeeding/breastmilk is a weak area for her.

EDIT: he’s 12lb 2oz and so far when my husband gives him a bottle, we struggle to get him to take 2oz