I'm very confused by this approach. You have two types of users "free and ad-supported" and paid subscribers. For the subscribers, it's easy. Take the amount t

I'm very confused by this approach. You have two types of users "free and ad-supported" and paid subscribers. For the subscribers, it's easy. Take the amount they pay, take a service fee, and the rest is allocated between the artists they play that month. The "free" users, take the ad revenue generated by the user (up to a cap) and allocate to the artists they play during a month. Pay on play really does not seem to work when you have two different revenue streams and you're trying to balance both.