I have an 06 GMC D/A, up until this year I swore of the additives because the dealer told me to, well at -40 the truck gelled twice, not a happy day for me, I was out looking at gassers the next day.
I called GM they said to use the additive...... On a side note, IA has very loose regulation on Diesel fuel, and they claim that is the issue, bad fuel.
From what I understand, the additive can dislodge debris, and since the Duramax fuel filters have very small holes, the filters get clogged much quicker, therefore using the additives may increase frequency of filter change.
I use the Power Services White bottle with red top. In the winter months 8oz per fill up... in the summer I will run 2-4 oz per fill up.