A member who makes the election described in Section 31778 shall receive a one-time lump-sum payment upon retirement in an amount as calculated below.
(a) A participant’s program account shall be credited with an amount equal to the retirement allowance the member would have received if the member had retired on the deferred retirement calculation date and had selected an unmodified allowance.
(b) The cost-of-living adjustments that would have been applicable during that period shall be included, applying the deferred retirement calculation date as the base year for the adjustment.
(c) All of the normal contributions that the member made under this chapter, plus interest applicable during the period from the deferred retirement calculation date to the election date.
(d) Some or all of the employer contributions made on account of the participant under this chapter, as agreed to in a collective bargaining agreement, plus interest applicable for the period from the deferred retirement calculation date to the election date.
(e) The member’s program payment shall be the amount calculated under subdivision (a) multiplied by the number of months in the deferred retirement period, plus the cost-of-living adjustment calculated under subdivision (b), the member contributions calculated under subdivision (c), and the employer contributions calculated under subdivision (d). The amount shall also include interest at a rate agreed upon in the collective bargaining agreement and adopted by the board of retirement, applicable to the amounts derived from subdivisions (a) and (b), for the period from the deferred retirement calculation date to the election date. The program payment shall also be credited with interest at a rate established by the board for the period from the election date until the payment is made.