As far as I know, FS has kept the 2 SFC for 3 SFB fighter ratio consistent for all fighter-using races.
In the beginning, the ISC had close to SFB compliments, in many cases on the 8 and 9 fighter carriers we had a 1 SFC to 1 SFB fighter ratio to make up for the lack of a "fighter heavy weapon". Firesoul, IIRC, added +20 damage to all ISC fighters, to increase their survivability against AMD when he put the ISC carriers on the same 3 -> 2 ratio everyone else has.