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 picked up under this subsection, and (ii) the picked-up contributions are in fact paid to the Fund as provided in the election.
If employee contributions are picked up under this subsection, they shall be treated for all purposes of this Article 11, including Section 11-169, in the same manner and to the same extent as optional employee contributions made prior to the date picked up.
40 ILCS 5/11-170.1