I don't think adaptive headlights work like this (I may be wrong), I understood the rear axle sensor to be for extra load in the rear of the car rather than for dips and inclines in the road.
Self-leveling headlights themselves have an additional level sensor that determines if the car is tilted forward or back. For example, if a car is driving over a large bump, when the front of the car hits the bump, it lifts up. Standard headlights would briefly point up into the sky until the rear of the car moved over the bump and the car returned to a level position. With a self-leveling system, electric servomotors react to the level sensor and keep the headlights aimed down at the road, no matter the position of the car.