where did you get those numbers from? Are you just guessing, or did you find some serious evaluation on the droppchances somewhere?
a static chance on loot doesnt really make sense. If a boss dropps 1 item for your class, and the other boss dropps 3, that essentially meanst that the one item from the first boss has a 3x higher chance to dropp (which doesn't at all fit the droppsystem on non-lfr bosses)