1. Look at the rate card for how many credits are used for each category.

2. Look at some of your typical sessions for token counts and calculate how many credits that would have been.

3. Look at the rates for extra credits (that's the only place credits have a price).

4. See that you are getting more than $200/mo worth of credits where we have evidence of the value of a credit.

If that doesn't clear it up, then I can't help, sorry.