Can a WD hitch be hitched at a vertical angle?

Thanks,

Do the bars impede the normal vertical angle travel of the trailer on the ball?

I only ask this because I also have to drive to my MILs farm which has tight hills worst than what I have drawn for the site above. This is in transit, so the bars would be set for travel. Also, the trailer frame is aluminum. I would not want a hitch that provided vertical resistance/stress in these situations, but I fear that is what a WD hitch is.