The videos show the difference between box squats and olympic style squatting. Squatting to a bench vs getting your butt to the floor. On the bench I could do 140kg for 6 reps while 135kg on the back squat was heavy for 1 rep. Both styles of lifting have their benefits and uses depending on what the end goal is.
One of the main benefits of powerlifting squats is that they are better for adding muscle and building brute strength because they allow for great loads to be handled.
Olympic style full squats are great for VmO (vastus medialis obliquis – or something latin like that) which helps prevent knee injuries. I also find full depth squatting easier on the knees than powerlifting style. If you want to snatch and clean big then you have to olympic style squat.
Are you box squatting, full squatting or not squatting at all?