How are averages calculated on the monthly plans?

Have you gone over on your monthly account? No worries, here's how we'll charge you for that:

0-100GB: $2.50/GB
101-1000GB: $2.00/GB
over 1000GB: $1.80/GB

Of course you can always switch your plan, but please note that the monthly accounts are essentially prepay, as you'll be paying in advance for the month's encoding, so when you switch your account, the overages will still exist.