Ah, I gotcha. Because he was on two different series. But he wasn’t actually a tactical officer on DS9; he was the station’s Strategic Operations Officer and the Defiant’s Executive Officer. Either way he’s still a bad ass and I voted for him.
I would question that source. The bridge stations and roles on the Defiant were kind of ill-defined. But to be sure, there were definitely times that he manned the tactical station on the Defiant, but then again, I think I remember seeing Garak at a bridge station at one point oz.