The city shall contribute to this system during each fiscal year an amount equal to the excess of the contribution required of and made by such employee to the county system over the contribution which would have been required of him or her as a member of the city system and with the same earned compensation. Such amount shall be credited to such employee and improved with interest in the same manner as if it were normal contributions under the city system. Should such member cease to be employed by the county through any cause other than retirement and should his or her accumulated contributions under that system be paid to him or her or his or her estate or designated beneficiary, such amount so contributed by the city, with credited interest shall be credited on the contributions required of the city to the city system. Upon the retirement of such member under the county system, he or she shall have the right to elect within sixty (60) days after the effective date of such retirement, without right of revocation, on and upon a form furnished by the retirement system manager, and upon completion to be filed with the city system, whether to have such amount with credited interest applied as accumulated additional contributions to provide an annuity for life in addition to any allowance to which he or she is entitled under the city system. Failure to make such election within such sixty (60) days or an election not to have such total amount so applied shall be deemed an irrevocable election to have such amount with credited interest paid to him or her in one sum, and such payment shall be made to him or her forthwith. (Prior code § 34.07.708)