I think I understood what you said, but I still don't understand your reason for saying it. ISTM it could be one of two things:
- The penalty for retiring early should be 5% or so because that's the difference in the actuarial value of the two pensions, or
- The penalty for retiring early should be 5% or so, even though that is more than the difference in actuarial value between the two pensions.
Which did you mean? and if the second, what difference does it make when people retire, as long as the actuarial value of each pension is the same? If, over a large number of teachers, the cost to the pension system is the same whether a teacher retires after 26 years with a $69K pension, or after 30 years with a $75K pension, IMO there is no benefit to anyone from forcing the first teacher to stick around for another four years.
Or did you mean something else altogether?