I may get flamed for this but here it goes.
I live in Michigan and between where I live and "going up north" my truck has seen
-15deg, over night on several occasions. I think I have plugged my truck in acouple of times in the almost five years I have had it, pretty much to see what the difference is. Truck is quieter on start up and heater works quicker, but that is it. I have never had any starting problems, fires up everytime, first time.
My procedure is this 1) If I use my remote start, start truck aprox 5 minutes before getting in, if cold enough high idle kicks in. Get in and go after that 5 minutes, which is usually after changing at work to go home.
2) If not using remote, and it is the first start of the day, jump in, start after "wait to start" goes out. Let idle a few minutes, usually untill grids stop cycling on the start up pattern ( usually 3-4 minutes) then go.
Either way, I go easy ie: under 10psi of boost and light throttle, until the temp gauge starts to move, then I drive as usual.
If it is real cold (being from Michigan that is relative) I may cycle the heater twice, but that is like below zero. Again I have NEVER had any cold start problems.
Remember Cummins/Dodge build these Engines/Truck for the Average owner, who is not going to read the manual, not cool down/warm up and generally drive like it is a gasser, and definately not going to join TDR and know how to do it correctly. Last I checked TDR had roughly 13,000 Members ( I may be wrong), but there has been 1,000,000 Dodge ram/Cummins configurations that have rolled off the lines over the years!
Just my opinion, hope this helps,
J-