The final details aren't published yet, but by based on what Apple has published you only qualify if you made less then $1m during 2020. If you exceed $1m at any point during the current year all sales for the remainder of that year are charged 30%. The following year all your sales from day 1 will be 30% for that entire year. If you fall below $1m for that year then you can reapply to qualify for the %15 fee for the next year.