Didn't they say that the FTL sensors had been damaged? And if not, it's not that hard to believe that they had been throughout the fight.
I haven't seen the episode in question. I've read about the maneuver, only. If damage to the FTL sensors was not specifically stated in the episode, then we're really grasping at straws to make this thing work. In my opinion, damaged FTL sensors would spell the end of the fight one way or another. The Enterprise
would be able to dart around anywhere delivering body blows to the enemy until they succumbed—without fear of counter strikes. It would not be necessary to "fake them out" by pretending to be two ships. Without FTL sensors, the Ferengi wouldn't stand a chance of hitting the Enterprise
, except by sheer accident.