I am one of those rare creatures that can squat MORE ATG than if I cut it a little high at or around parallel.
I think this is because I am more of an explosive lifter, but I am injury prone and stopping the weight at parallel is where most of my squatting injuries have occurred.
now that is true for RAW free squats (that means belt only or nothing at all for me)
with briefs, suits, box squatting, that is a different animal.
by best ATG belt only squat was 230-240kg. I routinely did 180-200kg for reps.
with suit, breifs, wraps and a belt off a dead parallel box I have done 680.