Heating oil is the same product as #2 diesel. The difference is taxes and the legality of running on the road. In my state heating oil is also ultra low sulfur. I've run my 790 John Deere compact tractor on heating oil for 26 years without an issue.
Heating oil has a very long shelf life; people have 40 year old tanks of it in their basements that are never drained empty or cleaned that keeps their homes warm.
It sounds like you passed up over $600 worth of fuel for your tractor.
My son just switched to LP from oil. I eagerly await the free 100 plus gals of "furnace oil" that will power my mowers for most of next summer.
Having been raised on a farm, transported fuels, and owned some gas stations the endless consternation on fuel compatibilities, fuel and gas shelf life continue to confound me.
I realize I am fortunate enough to have more experience on the subject than some, but despite endless posts on the topic we continue to make it complicated.
While there MAY be a "D" grade like Amoco used to ship via its proprietary pipelines, I haven’t heard of any. There is no furnace oil, there is no diesel. It’s all simply #2. In most states if it’s red, it’s not taxed for road use. Woe to those who get caught on the road with it. If it’s clear it’s good to go. Same fuel, probably 5 gals of red dye is all the difference.
Today’s “D" grade, if sold and uncharged as such would have about 7 gals of an additive per 7500 gal transport.
My simple rules:
In your tractor simply run #2, non taxable if available. Just like the farmers and contractors do. Additives year round are a waste of money. Buy me breakfast instead. LOL
In 2 cycle, straight premium, NO ethanol! I always add Sea Foam to my mix. Despite having 2 weed whips, 2 chainsaws, and a leaf blower I have not been in a small engine repair shop in approximately 20 yrs. Run em dry at the end of the year though.