It would appear that anytime when using dynamic brakes on Sherman Hill and then needing extra braking power, that the second you activate the auto brake or independent brake it shuts off the dynamic braking? This is not the way it works on SPG. So is this new system a bug or is it actually prototypical? Because it is making eastbound downhill runs extremely not fun to play.
You need to bail off the independent when applying the automatic brakes in conjunction with the dynamic brakes, (otherwise they cannot work effectively due to acting on the same wheels)