I had one guildie ask me how this macro was working for seduce.  When asked I hadn't had a chance to use it extensively yet, but in practice it worked like a charm.  This morning in Shadow Labyrinth I had a chance to use it extensively and am here to say that it worked like a charm!  I could just keep DPSing the MT's target while keeping my mouse button hovered over the macro to re-cast seduce when it ended.  I'd never even have to stop casting DPS spells on the MT's target.  It actually worked even better than I thought it would.  It'll still take some more getting used to, but it's just amazing what a difference it makes.