No, I'm addressing what you're saying. You tried to say that regenerative braking produced a net advantage, but this is not possible. Here's the source of your error:

> More stop and go with normal braking: -50% efficiency

Wrong value. Apart from the fact that the number is invented, because each stop turns all the car's kinetic energy into heat, the number should be -100%. Either that or perform a full analysis, with a listing of all the factors.

After you recover 20% of the energy with regenerative braking, you end up with -80% instead of -100%.

I'm saying that less drag and less engine speed are giving the fuel efficiency gains. I am saying that, typically, braking wipes out all of those gains and more. I am saying that regenerative braking often reduces the negative impact of braking enough that the gains -- from lower drag and engine speed -- aren't completely undone by braking.

I ride a low-power motorcycle. On the freeway, I get about 50 mpg. On back roads, with braking and generally higher rpm, I get 60+ mpg. For my low-power bike, the drag at freeway speeds takes more effort to overcome than does the varying speed and braking of back road riding.

And that is without regenerative braking. If I had regen braking, I'd get even better economy on back roads.