A 166 No.

I'm not sure what feat you're remembering (though I suspect that if you can't remember the name, you may be fuzzy on the details of the benefit), but a statement that you receive a fixed benefit doesn't change no matter how many times that statement is made.

Possibilities:
  • Vexing Flanker feat (Player's Handbook II):
    Benefit: You gain a +4 bonus on your attack rolls when flanking.
  • Swashbuckler class feature (Complete Warrior):
    Improved Flanking (Ex): A swashbuckler of 8th level or higher who is flanking an opponent gains a +4 bonus on attacks instead of a +2 bonus on attacks. (Other characters flanking with the swashbuckler don’t gain this increased bonus.)
  • Superior Flanking feat (Dragon # 343):
    Benefit: You gain a +6 bonus on attack rolls against opponents you flank. All allies who flank with you gain a +3 bonus on attack rolls against the opponents they flank.
    Special: The attack roll bonuses provided by this feat do not stack with the attack roll bonuses provided by flanking and improved flanking.