What I mean is this. A lot of programs and methodologies will have individuals shoot for a certain number of reps before raising the weight. You hear this all the time. "Once you get X reps, raise the weight Y percent."
So people will go and move some weights. Say one day they max out at 10 reps at a given weight. Two workouts later they squeeze out 13 and think "w00t! I caused more growth because I did more reps." Well, no, not necessarily. Past maybe 5 reps with reasonable negatives (2-3 seconds), doing more reps on top of that isn't going to add more growth.
There are other reasons to do higher rep stuff, though. Lactic acid promotes joint and connective tissue healing and can cause some sarcoplasmic (cosmetic, nonfunctional) hypertrophy.
That whole TUT thing is sort of tied in with that fact that with a moderate rep range of 8-12 you get a balance of sacroplasmic and sarcomore (functional) hypertrophy. The recommendation is based upon "gurus" just kinda noticing that they grew more doing this rep range. Individual recommendations of TUT sounds a lot like what some IART people do; it's based upon fiber twitch type and rate of fatigue factors that are only relevant to strength (not growth) training.
-casualbb