I guess it all depends upon how large the nicks are in the blade. Carbide can only be sharpened with a green wheel (silicon carbide) a CBN wheel (cubic boron nitride) or a diamond wheel so that may be an issue as to how you hold onto the small blade for sharpening.
I believe I also read that Festool matches the weight of each blade to the proper planer head so that the assembly is balanced at the 12,000 rpm speed. That results in a smooth surface finish.
Maybe a better approach is to use the beater carbide blade to clean up the surface and verify that there are no screws or nails present and then insert a new blade for the final surface removal. Granted it's a 2-step process but it may save you some $$ and frustration.