Formulae such as the one posted only serve to give a hint of how neurally efficient you are, not what fibers your muscles are predominately composed of.
And Louden, I, too, have seen substantial thigh thickening from Speed Squats.
As for heavy lifting being "easier" in a sense, I agree. The discomfort of lifting heavy is a welcome relief, compared to the searing of pushing my lactate threshold. Some people enjoy the burn, though. I actually prefer training with near-maximal and maximal singles, if I am comparing "feel", to doing anything as high as even 5 reps.
If it weren't for the structure of certain routines, I doubt I'd ever go over triples.
A Powerlifter once said, "Six reps, to me, is cardio." I'm not agreeing with him, but I know what he means, and it's not for lack of conditioning, either.
Lift on.