Hey Salzinni – I think it’s great that you learned to do proper muscle-ups from the beginning! Don’t get too hung up on doing lots of reps. I think 6-7 good, strict m-ups will do more for you than 15 sloppy ones.
Having said that, I’ve found the “rest/pause” technique very helpful for muscle-ups. Basically, you do your max number of reps, then rest at the top of the last rep for a few seconds and try to squeeze out one rep a time from there, resting in between reps in the top position above the bar.