1. In lieu of any benefit payable pursuant to section 87.237, any person who served as a firefighter and who is retired and receiving a retirement allowance of less than six hundred twenty-five dollars may act as a special advisor to the retirement system.

2. For the additional service as a special advisor, each retired person shall receive, in addition to the retirement allowance provided pursuant to this chapter, an additional amount, which amount, together with the retirement allowance he or she is receiving pursuant to other provisions of this chapter, shall equal, but not exceed, six hundred twenty-five dollars. Any retirement allowance paid to a retiree pursuant to this subsection shall be withdrawn from the firefighters’ retirement and relief system fund and no moneys shall be withdrawn from the general revenue fund of any city not within a county.