I was testing the billing feature for clients if I let them have control over templates and sending themselves. I didn't change the pricing structure back to 1cent plus $5, but reset the account to only allow reporting access for the client. When I went to pay for their campaign, even though the account was set for me to pay for the campaign, the rates were not my rates, they were the rates that I had entered previously before cancelling that feature.
When I went back to that client's settings, reactivated the edit templates and bill the client a different rate, reset the rate to 1cent plus $5, then cancelled it again to limit access to just reporting, everything was fine. (I didn't try lowering my own rate to see if I could create my own bargain - tsk tsk shame on you for thinking of that!)
Just want to let people know what's going on.