Can you provide a hypothetical example of a math error in a tariff formula and its direct impact?

Consider an electricity tariff with a tiered structure: first 100 kWh at $0.10/kWh, next 200 kWh at $0.15/kWh, and over 300 kWh at $0.20/kWh. A math error occurs if the formula for consumption over 100 kWh is coded as `(TotalConsumption * RateB)` instead of `(100 * RateA) + ((TotalConsumption - 100) * RateB)`. For a customer consuming 250 kWh, the correct charge for the first 100 kWh should be $10 (100*$0.10) and for the next 150 kWh should be $22.50 (150*$0.15), totaling $32.50. With the error, the customer would be charged $37.50 (250*$0.15) if `RateB` is used for total consumption, leading to significant over-billing and customer dissatisfaction.