(1) Any contractor obtaining benefits or payments under the medical assistance program to which such contractor is not entitled or in an amount to which such contractor is not entitled, shall be liable for such benefits or payments received and for interest on the amount of benefits or payments from the date of receipt until repayment is made to the department at the rate of one percent per month, unless the contractor establishes the overpayment was the result of errors made by the department.

(2) Interest charged by the department or interest expense incurred by the contractor, from whatever source, in making refund to the department shall not be reimbursable by the department as an allowable cost. The contractor may, by payment of a disputed settlement in whole or in part, stop accrual of interest on the amount paid. Such payment will be without prejudice to obtain review of a settlement determination.