Cold Weather Diesel Fuel Additive

I tried to head south from PA. last weekend, but an excess of "summer" fuel in the tank, and -8* Saturday morning derailed my plan. I first tried to heat the filter up, as I was assuming that it was icing. I was correct, in that the engine went from not starting to idling smoothly, but it would not run up and hold 1500-1800 RPMs without stumbling. I put a double dose of the PS White bottle additive in, and then stood inside the middle of the motorhome and rocked the whole rig back and forth like a retarded Gorilla, trying to mix the additive in. A few hours later it still brutally cold, but the rig was running fine..... sweet.