I see fuel economics like this:
Professionals like Ritch's Brew, most likely, buy nitro and oil 1,000 gallons at a time and methanol in lots of 10,000 gallons, thereby beating any one, five, or ten gallon deal by a huge margin.
They can mix and package the fuel and sell it at profit less expensively than you can do for yourself.
In "the good old days" around here we had Logghe Brothers Pro Power Fuel located in Roseville within seven miles of my home. I saw his fuel mixing building. It was a "don't try this a home, kids" deal. He had his worker carry the four-gallon cartoons to my car. He could judge nitro content by weight. When hefted a box of 40% he would say, "you got the good stuff".