(a)
(1) The annual benefit payable to eligible retirees, survivors, and beneficiaries of retirants of the Arkansas Teacher Retirement System shall be subject to a one-time ad hoc increase based on the retirant's years of credited service that is grouped within descending decades as calculated by subtracting the total years of credited service from the date of retirement.
(2) A break in credited service is not considered under this subchapter.
(3) Teacher Deferred Retirement Option Plan participants shall have the total years of credited service subtracted from the date of entry into the plan.
(b)
(1) One-half (½) of the annual dollar increase per year of credited service shall be calculated and provided to all retirees, survivors, and beneficiaries of retirants that are eligible to receive this increase.
(2) One-half (½) of the annual dollar increase per year of credited service shall be calculated then prorated based on the amount of contributory service credit to total service on the retirant's:
(A) Retirement date; or
(B) Plan entry date.
(3) The amounts under this subsection shall be calculated and provided to all retirees, survivors, and beneficiaries of retirants.
(c) The ad hoc benefit is payable to the retirees, survivors, and beneficiaries of retirants of the system beginning on a July 1 that is at least twelve (12) full months after the effective date of a monthly benefit.
(d) The ad hoc benefit for a retirant, survivor, and beneficiary of a retirant shall not increase the retirant's current benefit by more than twenty-five percent (25%) of the annuity benefit payable as of the prior June 30.