(a) The member's Teacher Deferred Retirement Option Plan account shall be the account in which shall be accumulated the:
(1) Plan deposits made on behalf of the member; and
(2) Plan interest.
(b) At the end of each fiscal year, the Board of Trustees of the Arkansas Teacher Retirement System shall credit each plan participant's plan account with plan interest on the mean balance in the account for the fiscal year.
(c)
(1) The board shall determine the plan interest rate to members' plan accounts based on:
(A) A fixed interest rate that is adopted by board resolution prior to the beginning of the fiscal year and which applies to subsequent fiscal years unless modified by the board; or
(B)
(i) A variable interest rate formula that is based on investment returns and other factors adopted by board resolution prior to the beginning of the fiscal year.
(ii) If the board uses a variable interest rate formula, the board shall adopt by board resolution the plan interest rate prior to the beginning of the fiscal year in which the plan interest rate applies.
(2) In addition to the applicable interest rate for the fiscal year, the board may adopt by board resolution a Teacher Deferred Retirement Option Plan participation incentive rate during a fiscal year if investment returns justify an incentive rate for the fiscal year.
(d) If a participant continues covered employment after completing ten (10) consecutive years in the plan, the participant's plan account shall be credited on June 30 of each year or through the date of retirement, whichever occurs first, with ten (10) year plus plan interest as set by the board.
(e) For the purposes of this section, the ten (10) year plus plan interest rate shall be the rate determined to be appropriate by the board and adopted by board resolution prior to the beginning of the fiscal year in which the interest rate shall apply.