if you have used one setup for 5 yrs then of course you will shoot it better than almost any new to you gun. You're just used to it and how it shoots and have the muscle memory. As far as shooting more paint, that's just a mental handicap like the other guy said. You don't have to shoot more with a semi. You need trigger discipline and need to move, play, take shots just like you would with a pump and only use the semi auto for a little personal god mode when stuff goes real bad. Kind like you would with an autotrigger.
If you can't do this with just discipline, play with a smaller hopper or stickfeed and enforce the limited paint mindset.
neither semi or pump is inherently more paint efficient(ok except maybe stockclass), It's just that our shot discipline typically goes down as the ease of shooting(fire rate) goes up.
I like both just fine. Stockclass: I am more likely to giggle like a girl when i shoot someone, but have done the same with a mech autococker so... yeah play both and enjoy