Quick-shifters are intended to operate at WOT, at high-rpm. Am I understanding that you're using it at 4krpm? or did you just set the minimum there?
In any event, you don't have a whole lot of time to get your kill time set right. It's easy to damage your trans quickly if you're not unloading it enough (not enough kill time)
Bascially, if you experience "notchy" and difficulty getting it shifted, you don't have enough kill time. Too much kill time is pretty self evident, because you can feel the bike jerk. The old DJ quick-shifters only gave you one setting for all the gears. The new(er) units let you adjust for all the gears, like kit ECU's do. The taller the gear, the less kill-time you need, and being able to run varying kill times is benificial for you and your trans.