Enai Siaion says:
If you have a mod that turns multiple surface types into the same texture, does it now qualify as one?
No. The original textures are the ones that matter.
@Everyone, I'll answer these questions ASAP, I'm really busy tomorrow but I'll try to find some time to give some answers to you guys!! The basic guideline is still the same though:
Different texture, different surface; Same texture, same surface.
(We still have to discuss through the road stuff, at least the ground/air thing. Thanks for your patience, we'll be back to you as soon as possible.)