(1) The benefit granted by this chapter shall not result in a total benefit less than would have been received absent such benefit.

(2) The total sum of the retirement allowances received under this chapter shall not exceed the largest amount the dual member would receive if all the service had been rendered in any one system. When calculating the maximum benefit a dual member would receive: (a) Military service granted under RCW 41.40.170(3) or 43.43.260 shall be based only on service accrued under chapter 41.40 or 43.43 RCW, respectively; and (b) the calculation shall be made assuming that the dual member did not defer any allowances pursuant to RCW 41.54.030(3). When a dual member's combined retirement allowances would exceed the limitation imposed by this subsection, the allowances shall be reduced by the systems on a proportional basis, according to service. The limitation imposed by this subsection shall not apply to a dual member with:

(i) Less than fifteen years of service credit in a plan with a retirement benefit cap as defined by the department; and

(ii) Service credit in a plan with no retirement benefit cap.