From my experience I can say you're wrong. What means is the average quality of the drill, not of each ability...
And, but I may be wrong, It seems to me that also the average of class skills (attack, defense, Physical e Mental) in some way influence the pace, since I notice that when I trained speed and form, already above 270%, to my aml.
His Physycal e Mental average was 112% and Long run trained at a good pace, despite it's not top class level. Training pass e dribbling with a top class training, was less efficient, despite they were around 220% (50% less than speed and form) but average attack was around 190%.
I'd need to test some another times with other players and collect some evidence of that, but I'm pretty sure that class skill average has some weight in the new training system.