overage charge
noun[C,usually plural]
ukusCOMMERCE
anextraamountofmoneythat you have topayfor using more of something than wasexpectedoragreed:
Withoveragecharges, she has hadcellphonebillsof $140 amonth.
Ifenergycostsincrease,tenantshave topayoveragechargestocoverthedifferencebetween thecurrentrateand theratewhen theysignedtheirlease.