(1) Notwithstanding any provision of law to the contrary, effective July 1, 1979, no person receiving a monthly benefit pursuant to this chapter shall receive a monthly benefit of less than ten dollars per month for each year of service creditable to the person whose service is the basis of the retirement allowance. Portions of a year shall be treated as fractions of a year and the decimal equivalent shall be multiplied by ten dollars. Where the monthly benefit was adjusted at the time benefit payments to the beneficiary commenced, the minimum benefit provided in this section shall be adjusted in a manner consistent with that adjustment.

(2) Notwithstanding any provision of law to the contrary, effective July 1, 1979, the monthly benefit of each person who either is receiving benefits pursuant to RCW 2.12.020 or 2.12.030 as of December 31, 1978, or commenced receiving a monthly benefit under this chapter as of a date no later than July 1, 1974, shall be permanently increased by a post-retirement adjustment. This adjustment shall be in lieu of any adjustments provided under RCW 2.12.037 as of July 1, 1979, or July 1, 1980, for the affected persons. Such adjustment shall be calculated as follows:

(a) Monthly benefits to which this subsection and subsection (1) of this section are both applicable shall be determined by first applying subsection (1) and then applying this subsection. The department shall determine the total years of creditable service and the total dollar benefit base accrued as of December 31, 1978, except that this determination shall take into account only those persons to whom this subsection applies;

(b) The department shall multiply the total benefits determined in (a) of this subsection by six percent and divide the dollar value thus determined by the total service determined in (a) of this subsection. The resultant figure shall then be a post-retirement increase factor which shall be applied as specified in (c) of this subsection;

(c) Each person to whom this subsection applies shall receive an increase which is the product of the factor determined in (b) of this subsection multiplied by the years of creditable service.