Xenon headlight adjustment
 

Been doing some highway driving at night recently and noticed that my xenon headlight beam pattern seems strange. It lights very well to the front right of the car, and ok at front left (not to dazzle oncoming cars) but in between the 'throw' of the light isn't as far. So there is a darker U-shape right in the middle in front of my car

Maybe my memory but I remember it having a very sharp beam cutoff line so am wondering if it needs adjustment. I did change the bulbs about 6 months ago

If so, if there a specific 'how to adjust' and what good looks like?