When a cost recovery fee is assessed upon any person in the manner provided by this Chapter, such fee will be due and payable on or before the last day of the month in which the notice of the assessment was mailed to the person assessed the fee. In the event of the failure of a person so assessed to pay any such fee when due, a delinquent penalty of ten percent (10%) shall be added to the fee on the last day of each month after the due date thereof, provided, however, that the total amount of such penalties shall not exceed fifty percent (50%) of the delinquent fees. In addition, in the event of the failure of a person assessed a cost recovery fee to pay such fee when due, that person shall be assessed interest on the amount of the delinquent fee, exclusive of any penalties thereon, at the rate of one percent (1%) per month, or fraction thereof, from the date the fee first became delinquent until the date the fee is paid.