(1) The amount of benefits payable to an individual for any week which begins in a period with respect to which such individual is receiving a governmental or other pension, retirement or retired pay, annuity, or any other similar periodic payment which is based on the previous work of such individual shall be reduced (but not below zero) by an amount equal to the amount of such pension, retirement or retired pay, annuity, or other payment, which is reasonably attributable to such week. However:
(a) The requirements of this subsection shall apply to any pension, retirement or retired pay, annuity, or other similar periodic payment only if—
(i) Such pension, retirement or retired pay, annuity, or similar payment is under a plan maintained (or contributed to) by a base period employer; and
(ii) In the case of such a payment not made under the Social Security Act or the Railroad Retirement Act of 1974 (or corresponding provisions of prior law), services performed for such employer by the individual after the beginning of the base period (or remuneration for such services) affect eligibility for, or increase the amount of, such pension, retirement or retired pay, annuity, or similar payment;
(b) The amount of any such a reduction shall take into account contributions made by the individual for the pension, retirement or retired pay, annuity, or other similar periodic payment, in accordance with regulations prescribed by the commissioner; and
(c) No deduction shall be made from the amount of benefits payable for a week for individuals receiving federal social security pensions to take into account the individuals' contributions to the pension program.
(2) In the event that a retroactive pension or retirement payment covers a period in which an individual received benefits under the provisions of this title, the amount in excess of the amount to which such individual would have been entitled had such retirement or pension payment been considered as provided in this section shall be recoverable under RCW
50.20.190.
(3) A lump sum payment accumulated in a plan described in this section paid to an individual eligible for such payment shall not be deducted from the amount of benefits payable to an individual for any given week.
(4) The resulting weekly benefit amount payable after reduction under this section, if not a multiple of one dollar, shall be reduced to the next lower multiple of one dollar.
(5) Any ambiguity in subsection (1) of this section should be construed in a manner consistent with 26 U.S.C. Sec. 3304 (a)(15).