If the provision authorizing the optional contribution requires payment by a stated date (rather than the date of withdrawal or retirement), the requirement will be deemed to have been satisfied if (i) on or before the stated date the employee executes a valid irrevocable election to have the contributions made on his or her behalf under this subsection, and (ii) the contributions made on his or her behalf are in fact paid to the Fund as provided in the election.
If employee contributions are made by the employer on the employee's behalf under this subsection, they shall be treated for all purposes of this Article 8, including Section 8-173, in the same manner and to the same extent as optional employee contributions made prior to the date made on the employee's behalf.
40 ILCS 5/8-174.1