Information is from Current ELM Manual Issue 42

566.34 Maximum Annuity Benefits

566.341 Eighty Percent Limitation

The basic annuity of a retiring employee may not exceed 80 percent of
high-3 average salary except when an annuity in excess of 80 percent results
from crediting unused sick leave. (See 562.4.) If an annuity computed under
the general formula exceeds 80 percent, it is reduced to an amount equal to
80 percent of the high-3 average salary. The reduction is made prior to
applying any reductions or increases.

566.342 Excess Service

If employees have service in excess of the years and months required to
provide the 80 percent maximum (usually 41 years and 11 months),
retirement deductions withheld after they have completed the service
requirements may be:

a. Credited to their voluntary contribution accounts if their regular
deduction obligations have been satisfied. (If employees owe a deposit
or redeposit, the money is first applied to that, and any balance is
credited as voluntary contributions.)

b. Refunded to employees if they elect the refund before their annuity is
granted and if no deposit or redeposit is due.

c. Paid in a lump sum to eligible survivors if the employee dies