They blend the same here from October straight through March, agreed on the rest of your post..
Since there are no federal regs regarding winter diesel, it's up to the seller (unless you have state regs) and they keep the blend/treatment to prevent waxing to "x degrees below the normal temperature for that month". I know here, it's difficult to get a straight answer when asked how/when they treat. For the most part there is no issue with a sliding scale through the winter to match temps since diesel is used as it is bought for use in trucks. Storing it for occasional winter tractor use raises the risk for me so I treat on my own. :thumbsup: