Fair enough - but my viewpoint (subject to review!) would be that, if the cable is loose under the capping, one cannot be sure that it is touching, let alone in good thermal contact with, the underlying wall - unless is is clipped to that wall.I take the viewpoint that the cable is not totally encased within the cap and heat can dissipate wall side, so that it will have no de-rating effects of capacity of cable. Ref C states "flat and touching" The cable is flat and touching the wall.
Kind Regards, John.