It seems like every few minutes would be fast enough, but whatever. It's just weird that, given how important app store purchases are for Apple, they wouldn't just spend any amount of money to make the best possible system: do the currency conversion, snap to those behavioral psychology price points, round to the prettiest unit... the works. Wouldn't everything be on the table for the thing that makes so much money?

Heck, maybe they did do that, and this 900 price point system is actually the right way to do it. Doesn't seem like it, but maybe!