Quote - Sunlight has a Shadow of .912.

No, it doesn't.  What that's saying is that for a 100% opaque material, 8.8% of sunlight will still pass through it.  Which is not correct.

That "lowering the shadow intensity" thing is a kluge left over from the older Poser days when IBL and IDL were not available to provide the ambient light that will make your shadows less intense.  The effect is the same---shadows that aren't dark---but one way is changing the rules of reality and the other recreates how those shadows become less dark in the real world.