104.100.  Early retirement and retirement, service credits required at age fifty-five — sixty — sixty-five, exception — computation. — 1.  Any member after attaining fifty-five years of age and having had at least ten years of creditable service may retire.  In such case, the member, except uniformed members of the highway patrol, shall receive an actuarial reduction approved by the board of the normal annuity he would have received commencing at his normal retirement age.

  2.  Any member after attaining sixty years of age and having had at least fifteen years of creditable service may retire with a normal annuity.

  3.  Any employee after attaining sixty-five years of age and having at least four years of creditable service may retire with a normal annuity.

  4.  Any member after attaining normal retirement age or early retirement age and who is entitled to a deferred annuity under section 104.035 may retire.  In such case, the member shall receive an annuity in an amount which is the actuarial reduction approved by the board of the normal annuity the member would have received commencing at the earliest date on which the member is entitled to an unreduced benefit based on the member's creditable service at the date of the member's termination of employment.

  5.  Notwithstanding any other provisions to the contrary, any member after attaining fifty-five years of age and having had at least thirty years of creditable service may retire with a normal annuity.