In addition to all other contributions required to be paid by the provisions of Sections 25-4-51 and 25-4-54, when the Unemployment Compensation Trust Fund of this state has received advances from the federal government under the provisions of 42 U.S.C. 1321, each contributory employer shall be assessed an additional rate solely for the purpose of paying interest due on such federal advances. The additional rate assessed to any employer shall be determined by dividing the estimated amount of interest to be paid on such advanced moneys minus any balance in this special fund by 95 percent of the wages as defined in Section 25-4-16 paid by all Alabama contributory employers during the immediately preceding calendar year. The amount to be paid by each employer shall be the product obtained by multiplying such employer's wages as defined in Section 25-4-16 for the calendar year immediately preceding the calendar year during which the advances became necessary by the rate as heretofore determined by provisions of this section. Each employer shall be notified of the amount of his or its assessment as required by this section not later than the fifteenth day of May next following the year in which such interest becomes due. Such amount shall be due and payable within 30 days of said notice and shall become delinquent on the day following such 30 days. Interest and penalties prescribed by the provisions of Sections 25-4-132 and 25-4-133 shall be applied to late payments to the same extent and at the same rates as is provided for delinquent contributions. Procedures for enforcing payment of amounts due including interest and penalty, by any employer shall be as prescribed by Section 25-4-134. Nothing contained herein shall prevent the Secretary of Labor from postponing the implementation of this section for one calendar year provided such postponement shall not delay collection later than required to pay accumulated interest when it becomes due to be paid nor shall it prevent him from making any further assessment if additional advances are made and/or additional interest becomes due.