Adjustable electric brake pros/cons

Are you sure about the "B" position? My Prius just runs at a higher RPM when I shift to B. I thought the extra braking with my foot off the brake was due to friction losses with engine connected and running at high RPM. Gas to engine seems off as MPG indicator is maxed out. Didn't thing Prius was using more than normal regeneration but I have no easy way to tell. Battery doesn't charge faster in B that I notice. Please tell me what you know.

 

B on the Prius is unlike downshift options on conventional automatics. It's purpose is to reduce charging, by using engine braking. It's main application is LONG downhill runs, where you run the risk of charging the battery to capacity AND subsequently overtaxing the conventional brakes.

Judging when that's gonna happen seems a tall order. AND, even if you don't switch to B in such a situation, the car will supposedly step in and do some B mode, behind the scene.

Bottom line, you very likely could never use it, with no ill effects.