I had similar "white smoke screen" problems on my 2009. The Dealer diagnosed it as a "bad charge air cooler" and replaced it IAW TSB 11-2-2. The Master Tech also told me the 6.4 is somewhat finicky regarding fuel quality. Unlike the 7.3, and to a lesser degree, the 6.0 which will run pretty happily on just about anything that will burn; the 6.4 really likes a steady diet of high quality, high cetane fuel. He equated the 6.4 to the engines in the old muscle cars that demanded "premium" fuel.
I am now running Murphy USA (Wal-Mart) or CountryMark Diesel R fuel along with Opti-Lube diesel fuel additive in every tank (includes cetane booster). No more "smoke screens", soot in the exhaust pipe is gone, mileage is fairly consistent at 15 mpg in city and 17-18 mpg on highway.