Cloth Modifier collision: Single Sided switch causing cloth mess

I spent 5 hours dropping a flattened half-UV sphere onto a horse back blanket. I wanted a part of a THICK leather saddle to drape WITHOUT WRINKLES. I started with the convenient Leather preset set at 80 and when dropped, it turned into a squirming, jittering wrinkled mess. I logically thought it might be something in the Physics settings so I kept putting in numerical changes and dropping AGAIN. I might as well tried my luck in Las Vegas. NO LUCK!
Then my lateral brain suggested the solution might lie elsewhere (the bar at the corner?) So I looked at the Collision settings for the blanket that I was dropping the “leather” onto and it had this box at the bottom checked; Single Sided. Everything else looked right so not having a clue at to what this is supposed to mean, I unchecked the box. The next drop acted just like the Physics except it was set at 100. There wasn’t a wrinkle and it worked great! This check box is clearly in the wrong place if it has this much Physics influence. It should be at the TOP of the Cloth Modifier Physics and labeled “Stiff or Wrinkled?”. Better would be a slide switch with those choices on each side.
I have screen-shots to show all of the above but as a newby it appears that isn’t permitted through this interface and probably not necessary in this case. (Version 2.90.0 2020=8=31)