(1) The retirement system may accept cash rollover contributions from a member who is making payment pursuant to section 24-706 if the contributions do not exceed the amount of payment required for the service credits purchased by the member pursuant to such section and the contributions represent (a) all or any portion of the balance of the member's interest in a qualified trust under section 401(a) of the Internal Revenue Code or (b) the interest of the member from an individual retirement account or an individual retirement annuity, the entire amount of which is attributable to a qualified total distribution, as defined in the Internal Revenue Code, from a qualified trust under section 401(a) of the code and qualified as a tax-free rollover amount. The member's interest under subdivision (a) or (b) of this subsection must be transferred to the retirement system within sixty days from the date of the distribution from the qualified trust, individual retirement account, or individual retirement annuity.
(2) Cash transferred to the retirement system as a rollover contribution shall be deposited as other payments for service credits.
(3) The retirement system may accept direct rollover distributions made from a qualified trust pursuant to section 401(a)
(31) of the Internal Revenue Code. The direct rollover distribution shall be deposited as all other payments under this section.
(4) The board shall adopt and promulgate rules and regulations defining procedures for acceptance of rollovers which are consistent with sections 401(a)
(31) and 402 of the Internal Revenue Code.