Damn, I'm not used to being the shortest guy in the room! I think when you go all the way down to your chest, you can hammer more weight. To me it seems like it would take some extra effort to stop the weightjust before it touches your chest.
BTW, that's pretty sick to be dunking in the 7th grade. I think I stunted my growth by starting to SFW at age 14. I was 6'2 when I was 14, but only grew another roughly 1.5" after that! I went to HS with this fukker who was 6'4 in the 8th grade, 6'10 by graduation, then grew another 1" after that. Yet, since he was 6'11 and 200lbs, the other ballers knocked him all around on the court. He basically sucked when he played college ball.