Found a billing error on a Duke Energy Progress account in Charlotte. The ratchet provision specifies billing demand as the greater of current demand or 75% of the highest demand in the preceding 11 months. The billing system was using 75% of the highest demand in the preceding 12 months ? including the current month in the lookback window. This creates a circular reference where a high current month both sets the current demand AND becomes part of its own ratchet calculation for the same bill. Small error but it compounds every month its applied.
Demand charge true-up errors ? utility applying wrong peak month
Angela ? thats a subtle but real billing system error. The ratchet lookback should be the 11 months PRIOR TO the current billing month, not including the current month. If the current month is included in its own lookback, any month that sets a new peak is automatically ratcheted by itself. How did you even catch this?
William ? I caught it by building a parallel billing model in Excel using the tariff language. When my calculated ratcheted demand didnt match the billed demand, I traced the discrepancy to the lookback window definition. Duke is including months 1-12 instead of months 1-11 in the ratchet calculation. Off by one month.
Angela ? this type of billing system programming error is more common than people realize. When utilities update their billing software, someone has to program the ratchet lookback logic. An off-by-one error in the lookback window definition affects every single account on that tariff. Have you checked whether this affects ALL Duke Energy Progress LGS accounts or just your client?
Richard ? I only have access to my clients account. But if its a billing system error rather than a data entry error, it theoretically affects every account on Schedule LGS with a ratchet provision. Thats potentially thousands of accounts. I reported it to Dukes commercial billing group and theyre investigating.
Update: Duke acknowledged the lookback window error. It affected approximately 2,400 accounts on Schedule LGS. Theyre issuing automatic credits to all affected accounts for the overcharge period. My client received a $4,200 credit. Duke thanked me for identifying the systemic error. Not a huge dollar amount per account but validates the importance of independent bill verification.
In my 30 years at Duke Energy on the metering side, billing system programming errors during tariff updates happened more often than anyone wants to admit. New tariff language gets translated into billing code by programmers who may not fully understand the tariff intent. Off-by-one window errors, wrong percentage applications, incorrect seasonal date boundaries ? Ive seen all of them. Angelas Excel verification approach is exactly right. Always model the bill independently.