Annuity in excess of that fixed in Sections 6--134 and 6--135 shall not be granted to the widow of an employee described therein unless the employee re-enters the service before age 63, in which case the annuity for his wife shall be fixed when he again withdraws or dies, whichever event first occurs, as of her age at the time the annuity is fixed.
40 ILCS 5/6-137