I am assuming (big, unfounded, no-data assumption here) that, with multithreading, instance-hours will roughly match CPU hours for most applications. Most apps take care to minimize actual request CPU usage, so most is in the API.

With the new changes, API time doesn't count, so all you're left with is pure CPU time. Since a single instance can service one request while waiting for another's API to return, you're pretty much limited by the CPU time you use.

I hope to be proved right, anyway.