Benefit formula. Benefit formula means the formula a defined benefit plan applies to determine the accrued benefit (within the meaning of section 411(7)(A)(i)) in the form of an annual benefit commencing at normal retirement age of an employee who continues in service until normal retirement age. Thus, for example, the benefit formula does not include the accrual method the plan applies (in conjunction with the benefit formula) to determine the accrued benefit of an employee who terminates employment before normal retirement age. For purposes of this definition, a change in plan provisions that applies only to certain employees who terminate within a limited period of time (e.g., an early retirement window benefit) is treated as a change in the plan's benefit formula for the employees to whom the change is potentially applicable during the period that the change is potentially applicable to them. The preceding sentence applies only to the extent that the change in plan provisions would result in a change in the benefit formula if it were permanent and applied without regard to when the employees' employment was terminated.