Delinquent child support and maintenance, interest on, rate, how computed

454.520. Delinquent child support and maintenance, interest on, rate, how computed — execution for interest, when, procedure. — 1. All delinquent child support and maintenance payments which have accrued based upon judgments or orders of courts of this state entered prior to September 29, 1979, shall draw interest at the rate of six percent per annum through September 28, 1979; at the rate of nine percent per annum from September 29, 1979, through August 31, 1982; and thereafter at the rate of one percent per month.

2. All delinquent child support and maintenance payments which have accrued based upon judgments or orders of courts of this state entered after September 28, 1979, but prior to September 1, 1982, shall draw interest at the rate of nine percent per annum through August 31, 1982, and thereafter at the rate of one percent per month.

3. All delinquent child support and maintenance payments which accrue based upon judgments of courts of this state entered on or after September 1, 1982, shall draw interest at the rate of one percent per month.

4. The interest imposed pursuant to subsections 1 to 3 of this section shall be simple interest. Interest shall accrue at the close of the business day on the last day of each month and shall be calculated by multiplying the total arrearage existing at the end of the day, less the amount of that month's installments, by the applicable rate of interest. The total amount of interest collectible is the sum of the interest which has accrued on the last day of each month following the first delinquent payment. This interest computation method shall apply to all support and maintenance orders, regardless of the frequency of the installments required by the court. If the order does not specify the date on which support or maintenance payments are to begin, it shall be assumed that the first installment was due on the date the order was entered, and subsequent installments fall due on the same day of the week, or date of the month, as is appropriate. Payments which were to begin on the twenty-ninth, thirtieth or thirty-first of any month shall be deemed due on the last day of any month not containing such date. The interest imposed pursuant to this section shall automatically accrue and attach to the underlying support or maintenance judgment or order, and may be collected together with the arrearage, except that no payment or collection shall be construed to be interest until the entire support arrearage has been satisfied. Such interest shall be considered support or maintenance for the purposes of exemptions, restrictions on amounts which may be recovered by garnishment, and nondischargeability in bankruptcy.

5. As a condition precedent to execution for interest on delinquent child support or maintenance payments, the obligee shall present to the circuit clerk a sworn affidavit setting forth the payment history of the obligor under the judgment or order, together with a statement which details the computation of the interest claimed to be due and owing; except, that the payment history affidavit shall not be required for periods during which the clerk is acting as trustee pursuant to section 452.345, or the division is acting as trustee pursuant to this chapter or any other provision of the laws of this state. It shall not be the responsibility of the circuit clerk to compute the interest due and owing. The payment history affidavit and statement of interest shall be entered in the case record by the circuit clerk. If the obligor disputes the payment history as sworn to by the obligee, or the interest claimed, the obligor may petition the court for a determination. The court shall hold a hearing and shall make such a determination prior to the return date of the execution, or if this is not possible, the court shall direct the sheriff to pay the proceeds of the execution into the court pending such determination. If the determination as made by the court is inconsistent with the payment history affidavit of the obligee, or the interest claimed, the amount of the execution shall be so amended.