Until about 3 years ago, you had to send in that form (actually a much, much shorter, simpler form) and get that end user ID number from the Comptroller and you could buy undyed diesel fuel for off road use without paying the taxes, which is what I did; never used any of the dyed fuel. On the old form you were simply swearing that you would not resell any of it, not use it in any on road vehicles, not buy more than X amount per month (some really high number; 10,000 gallons if I remember right). And a few years before that, you didn't even have to have the number; you simply signed a form at the distributor's office for them to keep on file stating that it would be used for off road use. Like everything else, they keep making it more and more complicated.