I’d put as much weight in Charlie’s estimation of percentage as I would in you training a non-powerlifter. This is from the same guy who so grossly “mismeasured” the weights Ben was benching and he “benched” 450×2 when he had intended on doing a submax 360×2. He never did a 1 rep max in squat, so you’ll never know the percentage. Most people can’t do 85% of their true 1RM for 6, let alone 90%.
And yes, most people can do 6 reps with an 85% load, that is how the RM chart was constructed. And…Ben wasn’t “most people”.