should i expres BF till empty?

I visited the LC from Thomsom PCC and they taught me express 15 mins + hand massage to release milk ducts x 3 cycle. Previously I had engorgement so they helped me to clear the block ducts. I also had sore nipple due to prolonged expression (30min cause spectra 9+). At home, I use spectra 9+ with 15 min cycle x3. However I dont feel that the milk has fully been empty from my breast. Should I continue more cycles or is it better to remain at 3 cycle? (At PCC they used medela hospital grade pump and able to pump 50ml in 1 cycle but with spectra 9+ I could only extract 30ml in 3 cycle) TIA