An employer who makes a deduction from a back pay award to an insured worker because of the insured worker's receipt of benefits under this chapter for which the insured worker is ineligible by reason of the back pay award, shall pay into the unemployment trust fund an amount equal to the amount of the deduction. If an employer making a payment under this section has already reimbursed the department for the benefits under AS 23.20.276 and 23.20.277, the account of the employer shall be properly credited. The insured worker's liability under AS 23.20.390 shall be reduced by the amount paid by the employer under this section.