Okay, I didn't mean to be confusing, but I'd like to try and clarify something. (Anyone who knows better about this, please correct me, but I'm pretty sure I am right.)
"Corrected grain" is used to refer to a few types of leather. All of them have had some treatment to the surface of the leather. However, not all will respond the same to different polishes, etc. I am certain that some leather is grain-corrected by sanding to smoothe the surface and remove minor defects, but not coated with anything plasticky. Then there are various grades of coatings that are applied. For example, Church's, Alden's and AE's corrected grain seem to be similar coatings. But they are completely different from the near-polyurethane (maybe it actually is?) of Kenneth Coles. These different coatings have different characteristics, such as how they bend/wrinkle, whether they will absorb or adhere any polish, and what it looks like if you chip the surface off. I've seen some Aldens and AEs with chips, and the leather underneath the surface is light tan, like the color of a scuffed sole. Contrast this to KCs which can't be chipped away because the surface is so soft and thick.
Maybe I will take some pics of corrected grain shoes I have lying around to help this discussion go somewhere.