The problem is with a light draw strop you use almost no effort to move the razor over it. With a heavy draw you are applying pressure whether you like it or not. So, is it the draw that makes the difference or the extra pressure you are wielding. I suspect it's the pressure and not the finish itself.
The only way to test that is with a stropping machine where you can dial in the amount of pressure exerted and I've never seen one of those.