There's no discontinuity in the first year you exceed $1m: that extra dollar is "taxed" at 30%, but the first $1m is at 15% ("the standard commission rate will apply for the remainder of the year").

Looks like the next year (after exceeding $1m) the first dollar will be taxed at 30%, though.

They should just make this work like income tax: the first $1m is taxed at 15%, and everything above that is at 30%. (Same rules every year, no flip-flop.)