(1) Except for those affected by subsection (4) of this section, a member of a retirement system specified by RCW 41.50.030 or, one previously established by the state but closed to new membership, may, as provided in each retirement system:
(a) Establish allowable membership service not previously credited;
(b) Restore all or a part of that previously credited membership service represented by withdrawn contributions; or
(c) Restore service credit represented by a lump sum payment in lieu of benefits.
(2) Persons who previously have failed to:
(a) Establish service credit for service previously earned; or
(b) Reestablish service credit by the restoration of withdrawn contributions or repayment of a lump sum payment in lieu of a benefit, may now establish or reestablish such service credit by paying the actuarial value of the resulting increase in their benefit in a manner defined by the department.
(3) Any establishment of service credit for service previously rendered, restoration of service credit destroyed, or repayment of a lump sum received in lieu of benefit must be completed prior to retirement.
(4) Service credit is established for or restored to the period in which the service credit is earned.