Payments to persons who are now receiving, or who may hereafter receive any disability or retirement payments under the provisions of chapter
41.24 RCW shall be computed in accordance with the last act enacted by the legislature relative thereto: PROVIDED HOWEVER, That nothing herein contained shall be construed as reducing the amount of any pension to which any firefighter shall have been eligible to receive under the provisions of section 1, chapter 103, Laws of 1951.