That seems like too much--is the every 3 hours around the clock? Total amounts for 24 hours for the BF baby average 25 oz, so that means a little over 1 oz/hr...range is 19-30 oz, so that means 0.8 oz/hr-1.25 oz/hr. So, feeding every three hours would be 2.4-3.75 oz ( http://www.kellymom.com/bf/pumping/milkcalc.html ). Though truth be told, I doubt 2.
4 oz per 3 hours is enough for most babies...