This workflow as a cheap and quick short cut to getting a starting for for textures before Substance Painter existed. If you want to lighten parts of the mesh that are facing up (which is ultimately what this is doing), there's probably a better way to do it with a smart mask or procedurally.
After playing around with Substance Painter a bit, I think the best way to do it would be with a mask + the Light generator. Point the vertical angle down at 270 degrees. There you can play with the highlight and falloff settings. Here's a recreation of this Base for diffuse setup. I didn't go all out and recreate the…