I noticed probably 15 years ago when my supplier filled my bulk tanks he then filled my inlaws heating oil tank from the same compartment. He confirmed to me at the time the only difference was the paperwork.
Yup... there might be some form of "taxation difference" depending on the use and the state you're operating in. #2 has more BTU's per gallon than #1. So you'll get better "fuel economy" out of the #2, and the higher you blend toward #1, the poorer your fuel economy will be. But #1 will burn alot "cleaner" too... city buses alot of times will run #1 all year round, just so that they don't generate smoke (image thing).
There USED TO BE a heavier grade than #2 for heating oil, which had more BTU's than #2, but it was about the same viscosity. Smoked more though, because of it being a heavier oil, without as many additives to help it burn cleaner, less lubricity agents because it wasn't intended to be run through a high pressure injection system, etc.
But then most of the "oil heating" went by the wayside... not many of those old oil burners left. So they quit that "grade" and just run the regular #2 off-road fuel.
ANYTIME your fuel tank (on equipment too) will be outside long enough to allow the fuel to get down below about 10 degrees (I was going to say 0, but you want a "buffer margin" here), you should be doing SOMETHING to help improve the flow/cloudpoint of that fuel. 10 degrees is where you'll sometimes START to see some clouding (wax crystal formation). Blend it appropriately for your area depending on how cold you expect it to get before you use up the fuel in the tank. If you're gonna get to just a little below 0 (say -10°), a good antigell added before cloudpoint will do you. If you're gonna get colder than that, THEN start adding in the #1... 30% down to -20°, 50% down to -30°, and 70-100% #1 below that... ALL with a good antigel treatment as well.
And if you've still got "summer fuel" in that tank, make SURE that you blend it down/treat it quicker... that is a slightly heavier cut of fuel out of the refining process than it is in winter too. Alot of times truckers will run into this... they might have "summer fuel" down there, longer than we would up here... and that will cause issues when they travel from south Texas to northern MN or Wyoming, etc.