It does not matter, because Naruto was using his KCM/SM and not his other power.
Even Naruto KCM has change, it does not matter, because now he has full Kurama.
lolwut
You said we shouldn't assume Naruto lost his Rikudo-powers in the Last because he demonstrated it in his final fight against Sasuke at VoTE. However, that fight ended at chapter 699, and the events of "The Last" occurs after it, hence why the movie was called "chapter 699.5".
Naruto did use RSM in the fight, as you have stated earlier, so aren't you contradicting yourself by saying Naruto was only using his "KCM/SM and not his other power"?