Kraken Pro vs “regular”

I want to make sure that I get this right: is it correct that paying for Pro is only worth it if you buy more than the Bitcoin equivalent of 500$ per month? if the fee for regular users is 1%, that would cost about 5$ for 500$, and the Pro subscription is worth a little less than 5$, so if you buy 500, you just about break even, right? Or do I miss something?