No, you start by 15% default until you reach the $1m threshold. After that you pay 30% for the remainder of that year. Please correct me if I'm wrong.

That's only if you're in the program.

If you get kicked out, you're stuck paying 30% for at least a year.

That is correct, but then the next year you start at 30%. So if you make slightly less next year you will end up earning less money that year since it is all at the 30% cut (And then the following year will fall back down to 15%)