Well, lets do the arithmetic.
The HAH has shown an average of 49 mpg over the miles that I've used it.
If I didn't have the HAH I'd have a reasonably efficient gas only car, so let's assume it would average 30 mpg.
I drive about 18K a year, so the HAH use 367 gallons and change over that period while the 30 mpg car would use 600 gallons, so the HAH uses 233 fewer gallons.
$100.00/.385=260 (rounded up to nearest tenth), so I'm paying the equivalent of a fuel tax on 27 more gallons than I'm saving and the difference would be greater if we assumed better fuel economy on the gas only car.
So yeah, I'm overpaying, while the EV driver is undercharged by a similar amount.