(

a) Upon reinstatement, pursuant to

Section 31680.4, the member’s rate of contributions and retirement allowance upon subsequent retirement shall be determined as if the member were first entering the system. Solely for the purpose of determining the member’s eligibility for service retirement under this section, service shall include the member’s credited service prior to reinstatement. (

b) The member’s allowance upon his or her service or disability retirement or other termination subsequent to the reinstatement shall be the sum of (1) his or her retirement allowance calculated on the basis of credited service rendered after reinstatement in accordance with the formula applicable to him or her plus (2) his or her retirement allowance as it was prior to reinstatement, adjusted by any change after reinstatement in the provisions governing the calculation of his or her allowance which would have applied to him or her had he or she continued in retirement. The retirement allowance otherwise payable under this

section to a member whose allowance prior to reinstatement was paid pursuant to his or her election under

Section shall be reduced as provided in

Section 31810. However, for a member reinstated pursuant to

Section 31680.4 prior to attaining age 62, the reduction required by

Section shall be the amount which is the actuarial value of the increase in the allowance from date of retirement to date of reinstatement. Notwithstanding any other provision of this chapter, the retirement allowance payable to any member subject to this

section for any credited service for which a retirement allowance was paid prior to reinstatement shall not be less than the retirement allowance which would have been payable on the date of the subsequent retirement had the member not been reinstated, adjusted, however, by any reduction under this

section because of an election under

Section 31810. (

c) Notwithstanding

Article 10 (commencing with

Section 31720), upon retirement for disability subsequent to reinstatement, a member shall receive a disability retirement allowance as follows:

(1) A service-connected disability allowance shall be equal to one-half of his or her final compensation or an allowance computed as prescribed by subdivision (b), whichever is greater.

(2) A nonservice-connected disability allowance shall be computed using the method prescribed by subdivision (b). (

d) This

section shall not be operative in any county until the board of supervisors, by resolution adopted by a majority vote, makes this

section and

Section 31680.4 operative in that county.