In computing service for pension purposes the following periods of service shall stand in lieu of a like number of years of teaching service upon payment therefor in the manner hereinafter provided:
The changes to this Section made by Public Act 87-795 shall apply not only to persons who on or after its effective date are in service under the Fund, but also to persons whose status as a teacher terminated prior to that date, whether or not the person is an annuitant on that date. In the case of an annuitant who applies for credit allowable under this Section for a period of military service that did not immediately follow employment, and who has made the required contributions for such credit, the annuity shall be recalculated to include the additional service credit, with the increase taking effect on the date the Fund received written notification of the annuitant's intent to purchase the credit, if payment of all the required contributions is made within 60 days of such notice, or else on the first annuity payment date following the date of payment of the required contributions. In calculating the automatic annual increase for an annuity that has been recalculated under this Section, the increase attributable to the additional service allowable under this amendatory Act of 1991 shall be included in the calculation of automatic annual increases accruing after the effective date of the recalculation.
The total credit for military service shall not exceed 5 years, except that any teacher who on July 1, 1963, had validated credit for more than 5 years of military service shall be entitled to the total amount of such credit.
Effective September 1, 1974, the interest charged for validation of service described in paragraphs (2) through (5) of this Section shall be compounded annually at a rate of 5% commencing one year after the termination of the leave or return to service.
40 ILCS 5/17-134