No, B-mode is just a convenience feature, same as Eco mode. Neither of them allow you to break the laws of physics. Eco mode just severely limits the motor power, and B-mode applies maximum possible regeneration with foot off accelerator instead of coasting. I almost never use Eco mode, but I think B-mode should be the default mode instead of D. It just feels so much nicer to drive. I get into a normal car with normal brakes now and wonder if they're faulty.