Thinking about the job I am completing- tub surround with cement board, hydroban over down on to tub flange behind stone tile. Permacolor grout, and I planned to Latisil the tile to tub joint. Now, wouldn't that trap moisture that was behind the surface of the tile at the tub deck, not allowing to drain out? I am going to go ahead with my original plan because I figure the moisture could be drawn through the tile. Right?