IS it? Because from what i read in their wording it seems like something you pay the moment you hit 200K$ in the last 12 months and get charged for it forward.Yeah exactly, and it's 200k USD / year too.
Definitely an issue for the more popular indie devs, but I cant imagine a nice porn game making that kinda sales-revenue on yearly basis.
Their page says new installs per month fee and it wouldnt make sense to have it work like "You have reached 200K$ in your 11th month but we wont charge you in the 13th month because your revenue isnt 200K per 12 month anymore."