Sorry for the late reply but I was just looking at my full carbon rails today when I removed it and noticed they are not at the same width as the mount either but not quite as misaligned as yours are. I never noticed when I originally mounted the seat to the bike but the rails do spread as you push into the mount groove with some flexing of the seat and I have at least a 1200 km on this seat now. The reason I removed the seat is I am having some trouble with the seatrails sliding backwards in the mount. Going to try and stick some very fine emery cloth in the grooves where the rails sit in the mount.
Have you gotten anywhere with SMP with the issue at hand. Seems strange that the chinese saddle has the right rail width and yet the actual manufacture does not.