Jim, Vin, we haven't really gotten an answer for why this has to be, yet. Only that it's "not above 100%".
Why can't it be more than 100%?
(For the rest of you: The reason you can only buy 9 at a time is because the inflation of the original price can't rise above 100%. So 9*10% is 90%, but 10*10% is 100%)