Budget Billing

Is anyone else on a budget plan for their energy bill?? We are, but I don't know why anymore. For the first 5 months, we paid "X" as our budget amount. I opened the statement today and they're charging us X+19 for this month's budget amount and I saw a note saying next month it will be X-6. Isn't the purpose of budget billing to pay the same amount every month for 12 months in a row?? And of course, I'm too impatient to wait the 9-13 minutes they're predicting on the customer service line, so I don't know why...