49 CFR § 378.2 - Definitions.
(b) Overcharge means an overcharge as defined in 49 U.S.C. 14704(b). It also includes duplicate payments as defined in paragraph (c) of this section and overcollections as defined in paragraph (d) of this section when a dispute exists between the parties concerning such charges.
(c) Duplicate payment means two or more payments for transporting the same shipment. Where one or more payment is not in the exact amount of the applicable tariff rates and charges, refunds shall be made on the basis of the excess amount over the applicable tariff rates and charges.
(d) Overcollection means the receipt by a household goods carrier of a payment in excess of the transportation and/or accessorial charges applicable to a particular shipment of household goods, as defined in part 375 of this chapter, under tariffs lawfully on file with the United States Department of Transportation's Surface Transportation Board.
(e) Unidentified payment means a payment which a carrier has received but which the carrier is unable to match with its open accounts receivable or otherwise identify as being due for the performance of transportation services.