My A3 e-tron uses less energy the more I use regenerative braking, and I suspect the e-tron will as well, but I haven't done any testing. and like chrisjenx said, it really doesn't make sense, since the purpose of regenerative braking it to recuperate energy. And as I understand it, when you apply brakes up to what would be the equivalent regeneration level, the braking uses regeneration. Beyond that, the regular brakes kick in. Seems like it is just the mechanism that is different, not the actual energy use. But I am open to correction. BTW, I wish the regenerative braking had a more aggressive level to choose.