best piece of advice I ever read on rep ranges was from the late Dr Ken Leistner I think in 'the steel tip' - it was reprinted in 'hardgainer' magazine . Like everything else some advice is good some bad, work out what works for you etc.
Anyway he talked about how some people are just wired CNS to do certain rep ranges, and it can vary from person to person and muscke group to muscle group. His exampe was the at the time NFL strength test where his adopted son got something like 20-23 reps (iirc correctly the test was max reps with 225). He made the point that his son then went on to do 17-18 reps with 315 even though that wasn't the test parameter. Point being he 'gassed' at around 20 reps in the exercise.
Long story short, I was always good (for me, relatively speaking) doing slightly lower reps on pressing exercises, seemingly just how Im wired up, but could go higher with rowing/pulling. Lower back and lower body lower reps worked better. When I abandoned the 'need' to stick to certain rep ranges and focussed on what worked for which muscle groups for me, I made more progress. In real world terms that meant anything from 3-8 reps for pressing and about 8-20 for rowing. Calves I could do anything pretty much as long as I 'did' train them.