Any sugars in your recipe? They are very fermentable and will increase your overall attenuation.
What was your fermentation temperature? Higher fermentation temperatures will help the yeast ferment more completely.
No sugars. Temps were normal, about 64-66 on the fermometer. I think I'm just getting really efficient in the mashing process and now with my improved water chemistry, I have to really pay attention to my sacc rest times or else I'll consistently have really dry beer.