That’s a Koro specific weakness he pleaded for. Itona has nothing to do with it. Refer to
this thread, specifically to
this post, if you want a more in-depth answer.
They wouldn’t; none kept up with a not holding back Kaede.
Already talked about this, so I'll restate it here.
She was up in the air with no way to maneuver, trying to aim at Okano, and Kimura comes directly from behind and shoots her in the back. This is not a blitz, it has nothing to do with perception. Even if it were, that’d be an outlier for Kimura, not an anti-feat for Kaede. We know that she still has that kinetic vision of tentacles, regardless of the Reaper thingy, she'd have a perception speed of at least Mach 20, while Kimura is clearly nowhere near that either.
btw, one minor thing, calcs are speculative fan things; she is (perception-wise) faster than him, sure, but you can't really say 80 times as if series acknowledges the numbers here.
These are non-factors.
So two points:
Reaper blitzed her so no (btw, Reaper doesn't downscale from Karasuma; I'd even say he has a slight edge over him).
And that why would she be faster than Koro?
The first is wrong. Kaede clearly said she could and was about to kill Reaper at the time he was bullying 3-E.
Already talked about the second one, but to restate it once more:
I mean, Itona also blitzed Koro. Almost all tentacle life-forms differ from each other in more than one category.
As for the question, it isn't explicitly explained; it may be that her tenacity was so good that tentacles amped her up to that level. I can think of one or two plausible explanations, but none explain this without speculation.
In any case, it is what it is.
I'm not entirely sure, but it seems fine for now, so I’ll agree.