Jon -
Thanks for the correction - 15% solution, not 20%.
I do think it's pretty simple. The SCTA has a definition of what constitutes gasoline, and an absolute method of testing it.
Everything else is fuel, or diesel.
If E-85 eventually works its way into being a common fuel (it's not at the present, despite its increasing availability here in Corn Country, where it has political advocates), at that point, I would agree that the SCTA should look at it for production classes.
But realistically, I don't see it becoming available universally. Let's face it, if one were to try to travel from LA to Loring in a car that was designed to run only on E-85, it would be a long trip with many side trips to small rural communities with farmer's cooperatives that actually sell it in order to fuel up.
That said, I remember the 10% alcohol blend being poo-pooed, and now it's common. But it took thirty years for that to happen. I don't see E-85 around in thirty years - not with the corn based system of producing ethanol that we have now. But if I'm wrong, I also have no doubt that the SCTA will adopt such a change, just as they did when 10% solutions of gasoline and alcohol started becoming common.
I think it's too early in the game to adopt an E-85 rule for production classes. Let's see how the product plays out in the market in the long run.