(a) When an award is appealed and subsequently is affirmed by a court, the interest shall be computed from the date on which the award notice was filed in the department to the date of payment of the award, except as provided in section 27 of the Workers' Compensation Law.

(b) In all other cases interest shall be computed from 30 days after the date on which the award notice was filed in the department to the date of payment of the award, except as provided in section 27 of the Workers' Compensation Law.

(c) In any computation under subdivision (a) or (b) of this section, interest shall be computed on the amount of the award, including the attorney's fees, and payable to the claimant. The attorney shall not be entitled to interest on his fixed fee.