(a) As used in this section the term “State or Federal benefit” means a payment to an individual on account of total or partial disability or death due to pneumoconiosis only under State or Federal laws relating to workers' compensation. With respect to a claim for which benefits are payable for any month between July 1 and December 31, 1973, “State benefit” means a payment to a beneficiary made on account of disability or death due to pneumoconiosis under State laws relating to workers' compensation (including compensation for occupational disease), unemployment compensation, or disability insurance.

(b) Benefit payments to a beneficiary for any month are reduced (but not below zero) by an amount equal to any payments of State or Federal benefits received by such beneficiary for such month.

(c) Where a State or Federal benefit is paid periodically but not monthly, or in a lump sum as a commutation of or a substitution for periodic benefits, the reduction under this section is made at such time or times and in such amounts as the Office determines will approximate as nearly as practicable the reduction required under paragraph (b) of this section. In making such a determination, a weekly State or Federal benefit is multiplied by 41⁄3 and a biweekly benefit is multiplied by 21⁄6 to ascertain the monthly equivalent for reduction purposes.

(d) Amounts paid or incurred or to be incurred by the individual for medical, legal, or related expenses in connection with this claim for State or Federal benefits (defined in paragraph (a) of this section) are excluded in computing the reduction under paragraph (b) of this section, to the extent that they are consistent with State or Federal Law. Such medical, legal, or related expenses may be evidenced by the State or Federal benefit awards, compromise agreement, or court order in the State or Federal benefit proceedings, or by such other evidence as the Office may require. Such other evidence may consist of:

(1) A detailed statement by the individual's attorney, physician, or the employer's insurance carrier; or

(2) Bills, receipts, or canceled checks; or

(3) Other evidence indicating the amount of such expenses; or

(4) Any combination of the foregoing evidence from which the amount of such expenses may be determinable. Such expenses shall not be excluded unless established by evidence as required by the Office.