(a) A person who is eligible for the benefits provided under Section 11-133.3 and who, if he or she had retired on or before February 29, 2004, would have been entitled to a pension equal to 80% of his or her highest average annual salary for any 4 consecutive years within the last 10 years of service immediately preceding February 29, 2004 without receiving the benefits provided in Section 11-133.3, may elect, by filing a written election with the Fund by January 30, 2004, to receive a lump sum from the Fund equal to 100% of his or her salary on February 29, 2004 or the date of withdrawal, whichever is earlier. To be eligible to receive the benefit provided under this Section, the person must withdraw from service on or after January 31, 2004 and on or before February 29, 2004 (or the date established under subsection (b), if applicable). If a person elects to receive the benefit provided under this Section, his or her retirement annuity otherwise payable under Section 11-134 shall be reduced by an amount equal to the actuarial equivalent of the lump sum.
     (b) To ensure that the efficient operation of employers under this Article is not jeopardized by the simultaneous retirement of large numbers of critical personnel, each employer may, for its critical employees, extend the February 29, 2004 deadline for terminating employment under this Article established in subdivision (a) of this Section to a date not later than May 31, 2004 by so notifying the Fund by January 31, 2004.