A participant in the Arkansas State Police Officers' Tier Two Deferred Retirement Option Plan:
(1) Shall not have a change in his or her monthly retirement benefit unless the plan receives a benefit increase; and
(2) Shall earn interest at a rate set by the Board of Trustees of the State Police Retirement System that shall not be greater than five percent (5%) nor less than one percent (1%) per annum as determined by the board from time to time as promulgated by rule.
(3) The interest shall be credited to the individual plan account balance of the participant on an annual basis.