The adjustments provided by this article are subject to the following limitations:
(a)
No adjustment shall be made for any year for which the adjustment is less than 1 percent of the base allowance, and the adjustment for any year shall not exceed 6 percent of the base allowance.
(b)
No monthly allowance in any year may exceed an amount equal to the base allowance increased by 2 percent per year compounded for the number of years
intervening between the end of the base year and the beginning of the calendar year in which the adjustment is made.
(c)
No monthly allowance in any year shall be less than the base allowance.
(d)
No adjustment shall be made in any year in which the actuarial interest rate is less than 4.5 percent.