Not sure if this would help all that much but have you tried cycling your glow plugs a couple times before firing up the truck?

From my understanding, white smoke on ignition comes from unburnt fuel. There is a good chance your engine is surging cause of the cold, mine does that too some mornings.

My $.02, find a GOOD diesel mechanic in your town and stop going to the dealership. They'll @#$@#$*@&#$(*&# you all day long. I've never heard of a dealership that has the customer's best interest in mind. A local small shop with a good owner might be the other way around.