An allowance computed in accordance with Section 2.124.1550 of this chapter shall be modified upon receipt by the eligible member of old-age primary insurance under the Federal Social Security Act, in accordance with Article X of this chapter. The amount of said reduction shall be computed upon the assumption that compensation paid to said member by the county which entered into the computation of the old-age primary insurance amount payable to said member under said act was instead paid to said member by the city and all provisions of said Article X shall be applicable to said member to the same extent as if he or she had remained in the employment of said city until date of retirement and had elected to obtain coverage under said act as an employee of said city. (Prior code § 34.07.714)