Should any miscellaneous member cease to be employed as such a member, through any cause other than death or retirement, all of his contributions, with interest credited thereon, shall be refunded to him subject to the conditions prescribed by the Board of Supervisors to cover similar terminations of employment and re-employment with and without redeposit of withdrawn accumulated contributions of other members of the Retirement System, provided that, if such member is entitled to be credited with at least five years of service, he shall have the right to elect, without right of revocation and within 90 days after said termination of service, or if the termination was by lay-off, 90 days after the retirement board determines the termination to be permanent, whether to allow his accumulated contributions to remain in the retirement fund and to receive benefits only as provided in this paragraph. Failure to make such election shall be deemed an irrevocable election to withdraw his accumulated contributions. A person who elects to allow his accumulated contributions to remain in the retirement fund shall be subject to the same age requirements as apply to other members under Section 8.584 for service retirement but he shall not be subject to a minimum service requirement. Upon the qualification of such member for retirement by reason of age, he shall be entitled to receive a retirement allowance which shall be the actuarial equivalent of his accumulated contributions and an equal amount of the contributions of the City and County, plus 12/3 percent of his average final compensation for each year of service credited to him as rendered prior to his first membership in the Retirement System. Upon the death of such member prior to retirement, his contributions with interest credited thereon shall be paid to his estate or designated beneficiary.