Settings are the same for all servers .
There is no trick or anything else.

Not only ppm counts for rating avg rating + avg ppm and many other factors .. depends what is your map rating average check ur player stats etc.
also Fa 2 has if im right xp_damage set to 1 which mean u get xp just by hitting someone , even if u dont kill him u get XP .

+ something important , there is no limit for rating , contrary to SL . On TB you arent limited at (3x avg ppm)