I find monthly billing of usage based services to be very user unfriendly: * I pay for 100,000 queries even though I made only 50,000. * I need to upgrade as

I find monthly billing of usage based services to be very user unfriendly: * I pay for 100,000 queries even though I made only 50,000. * I need to upgrade as soon as my usage goes over the plan limit. And then, I need to remember to downgrade. Be fair, charge by usage.