Pumping times at work.. need advice

Hey everyone! I just returned to work last week and feel like I have been pumping a little less everyday. My first day back I pumped 12 oz and now on average I pump 8 oz. I have been pumping 4 times a day. 7 am, 10 am, 12 pm and 1:30 pm. Today because of scheduling issues I was not able to do my 12 pm and 130 pump. I was feeling very uncomfortable and was finally able to pump at 245 and ended up pumping way more than my usual. Today I pumped 10.5 oz total vs the 8 total I have been doing all week. Do you think I should be pumping less maybe 3 sessions? or keep pumping 4x a work day? I feel that I respond to the pump better when slightly engorged