A. Fast Meters. If a meter is tested and found to have over-registered more than 2 percent, the utility shall recalculate the bills for service of the last customer of record receiving service through the meter and shall make a refund if the amount of the adjustment exceeds $1. The refund shall be for the period that the customer received service through the meter, but for not more than the periods established below:
(1) Known Date of Error. If the date on which the error first developed or occurred can be established, the bills for service shall be recalculated from that time.
(2) Unknown Date of Error. If the time at which the error first developed or occurred cannot be established, it shall be assumed that the over-registration existed for a period of 3 years or a period equal to one-half of the time since the meter was last tested, whichever is less.
B. Slow Meters. Whenever a meter is found to be more than 2 percent slow, the utility may bill the customer one-half of the unbilled error for a period of 12 months, unless the meter has been tested within that 12-month period, in which event the utility may bill the customer one-half the unbilled error for the period since the meter was last tested. If the amount of under-registration is less than $5, the utility may not adjust the bill.
C. Accuracy Calculations. Billing adjustments due to fast or slow meters shall be calculated on the basis that the meter should be 100 percent accurate. For the purpose of billing adjustment, the error in registration of the meter shall be calculated and applied as specified in COMAR 20.70.06.04.
D. Overcharge Adjustment. When a customer has been overcharged as a result of incorrect reading of the meter, incorrect application of the rate schedule, incorrect connection of the meter, or other similar reasons, the amount of the overcharge shall be refunded or credited to the customer, except for an overcharge resulting from an incorrect reading of the meter where the amount will automatically be corrected in a subsequent billing based on a correct meter reading.
E. Undercharge Adjustment. When a customer has been undercharged as a result of an incorrect reading of the meter, incorrect application of the rate schedule, incorrect connection of the meter, stopped meter, or other similar reasons, the amount of the undercharge may be billed to the customer. However, the utility may deny service for non-payment only for that portion of the undercharge applicable to the 4 months immediately before the discovery of the error, unless otherwise authorized by the Commission.