If the statutes, ordinances, rules, regulations, or orders of any public agency are so changed, or if for any other reason the effect of the increase of the retirement allowance or other benefit payable to any beneficiary pursuant to the provisions of this chapter on the amount of any monetary payments due to the same beneficiary by such public agency are changed, the board shall adjust such retirement allowance or other benefit, but not to an amount greater than otherwise authorized by this chapter so as to result in the maximum total benefits to such beneficiary.