Found a classic digit transposition on an IPL account in Indianapolis. Meter reader recorded 35,847 kWh instead of 35,487. That 360 kWh difference on a 40x multiplier became a 14,400 kWh overcharge on a single month bill. At roughly 9 cents per kWh all-in, that is about $1,300 on one month. But here is where it gets interesting — the following month, the next actual read was correct, but because the previous read was inflated, the delta between reads showed abnormally LOW usage. The billing system flagged it as a potential meter error and switched to an estimate for that month too. So now you have one month overbilled and the next month incorrectly estimated. It took 3 months for the billing to normalize. Total overcharge across the affected period was about $4,200.
Digit transposition in meter read — $4,200 overcharge
The cascading error effect is what makes these so insidious. One bad read throws off the next 2-3 months of billing because the system tries to self-correct based on wrong data. I have found that plotting monthly kWh on a simple line chart is the fastest way to spot these — you see a spike followed by a dip (or vice versa) and then a gradual return to normal. If the spike/dip pattern does not correlate with any operational change at the facility, it is almost certainly a reading error.
Good tip Ray. I have started doing that for every audit now — 24-month chart of kWh and kW demand. The visual anomalies jump right out. IPL processed the correction in about 3 weeks once I showed them the math. Straightforward claim but a nice $1,470 fee at 35%.