Definition of 48) “Supplemental cost

48) “Supplemental cost means an element of the total actuarial cost of a defined benefit retirement plan arising from benefits payable for service performed prior to the inception of the retirement plan or prior to the date of contribution rate increases, changes in actuarial assumptions, actuarial losses, or failure to fund or otherwise recognize normal cost accruals or interest on supplemental costs. These costs are included in the unfunded actuarial liabilities of the retirement plan.