The game engine does not take height into account.
OK, then maybe the 2:1 experience/rebounding weight would be a simple way that the tip skill could be implemented. 2 to 1 is also the weight I would put on the chances that the tip is determined in the game engine by a pure coin flip vs. considering players skills and experience somehow... it's just not that important in the big scheme of things.
BTW, I understand that skills and not height are what matter for things like rebounding and inside skills, but jump balls are probably something that (if it was deemed worthy to really try to get it right)
should depend on height directly to some degree.