Thats not an excuse unless you think thats his top speed in kcm. Sasuke moving faster in that instance is all you really have.
Unless you have a proof, then it is a made-up excuse, when Sasuke has evaded C2 bomb's detonation velocity without getting a scratch on himself, and then jumped up to evade another shockwave. That's two shockwaves in a single instance. An area that was more than thrice the size Minato covered in his best speed feat to dodge what? A Kurama's claw? C2's D-velocity is 22 mach. And guess what? Those were Hebi days.
What are KCM Naruto's speed feats? He is inferior in every aspect. V1 and V2 Jins reamed his ass: He got kicks on his jaw, got roasted, had a rock-like tech clamped to him, V1 Ae punched him around as if he were a ragdoll ... all the while Bee kept stepping in repeatedly to save him. Obito in base took out
TWO or THREE of his KCM clones while standing STILL. Yeah, he was only moving his arm to use Gunbai. His legs were perfectly still. He didn’t move from point A to B and still owned Naruto’s little punk ass and the “speed that cannot be topped!” He reacted and easily used Kamui to warp away, when for Hebi Sasuke, he had to use Intangibility; n fact, it is an automatic tech.
So, let me ask you this: he didn't think about using his TOP SPEED any time when the aforementioned mishaps happen? Don't be ridiculous. I know you favour Naruto, but this is just nonsense. This is nothing but fiction. The fate of the world hung in the balance … nah, he isn’t using his top speed.
KCM Naruto was never that fast. It was not until his battle with Obito in BM form that he gained that speed. Sasuke has always outclassed him. This would be one of the aspects.