It doesn't really matter that you can't measure it:
In D mode, you press the brake pedal when you need to slow down and it regens to 0.25G and uses the brakes thereafter above 0.25G.
In B mode, the car slows by up to 0.25G effort needed by regen, and if it's not enough, you then have to start using the brake pedal too, to go beyond it.
Either way, if you need less than 0.25G, the regen will take care of it, whether you instigate it by coming off the accelerator or use the brake pedal, and either method need the brake pedal beyond 0.35G requirements.
Having the car feel like you left the handbrake on just feels crap to me. I want to come off the accelerator down a slight hill to maintain speed or on the approach to a roundabout, then brake when I need to.