Under Article 13.4(b)(iii), the French agency will compute the amount of the benefit it will actually pay by prorating the theoretical amount determined under Article 13.4(b)(ii).  The pro rata benefit will be computed by multiplying the theoretical amount by the ratio of the periods of coverage under French laws to the total periods in both countries.  To avoid an excessive pro rata reduction for workers with many years of coverage under the  U.S. and French systems, the denominator of the ratio is limited to the number of quarters of coverage required for a full old-age pension under French laws—currently 150 quarters.