rounding

squats: 285 x5, x4, x2.
bench: 160 x5, x5, x3.
cleans: light day = 95x5, x5, x5; 105 x5; 115 x5.

I received the feedback from the gym supervisor that, during the squat, when I am going back up the arch in my lower back deteriorates and becomes rounded. In the 3rd set I tried to keep it arched but bailed after the 2nd rep when I couldn't.

Also, got my copy of "The Strongest Shall Survive" by Bill Starr and am giving his program a try with the cleans.