Jack - I was told to do as you are doing - wean down in dosage every couple of weeks, but my notches down were by 25 mg. rather than your 50. Folow your doctor's orders. Just don't do it in a hurry...if you can live with 50 well, then do that for a bit and then go down more.
Be sure to ask him what to do should afib flare up again, though, so you are prepared.
Good luck...let us know when you are Flec free and how it goes.
Jackie