For those of you that pump at work when do you pump, how long does it take you and how much do you get on average during each session?

I'm only day 3 back at work and thus far I nurse before leaving around 730am and pump the other side and get about 1oz. Pump around 11/11:30 am and 3/3:30 pm. I get about 4oz each session. Not much and def not enough so we supplement with formula. Then I go home and nurse as soon as possible. I'm thinking I should try to pump while nursing at home too. But I miss the nursing and don't want to disturb it. And sometimes she gets agitated if I pump while nursing!

I would really like to pump once more during the work day. But not sure if I would get much more. I'm thinking since it will bring the time in between pump sessions closer I might get about 3oz each session. Bringing it up to total of 9oz for the day only about 1 more oz so is the extra 20 minutes of pumping worth the 1oz??