Dealer installed mine September a year ago (16 months ago). Have towed a few thousand miles now. On our last trip (Florida over Christmas), I noticed the first time that my bars are angled up and not parallel to the trailer frame. Funny, I finally noticed this after so long. I've had no problems towing or unhitching. To unhitch, the trailer tongue has to raise high enough to let the pressure off so they slide off the L bracket easily. Mine came with a funny looking cheater bar, but I've never used it, no need to. I always make sure I can raise the tongue high enough. I carry extra blocks when going to a new or unknown campground so the tongue jack can be raised higher in the event I found myself on an unlevel ground (which has not happened yet).
So parallel? I'm sure that is best, but so far, I've not had any problems with mine. My philosophy ... if it's not broken, don't fix it. But I will reevaluate this come spring when its a bit WARMER outside and can fiddle around.