Robert, everything you say seems totally sensible to me. Like I said, my issue was with the degree of costs allocated. A flat fee would seem quite sensible.
BTW, vfx, I hate to say it, but I do understand the eventual need for an EV road tax (or any non-road taxed fuel vehicle).
In both cases however, I think the public good of encouraging adoption means we, as a society, should delay these as long as possible. It takes a pretty significant percentage to materially effect the economics of the system. e.g. If only 1% of cars are EV, then it's not really affecting wear and tear of roads enough to matter. But 20% would make a pretty big difference so somewhere between those two it is necessary to start having EV drivers help pay to maintain the roads. This is basically the same problem faced by utilities. I'm not sure what percent of electricity is being produced by private solar at this point, but I'm guessing it's still pretty small.