Whirlwind Shield jump with Knuckles is low... Is it intentional?

As you can see in this video below, Sonic jumps a lot higher than Knuckles using the shield even almost at the same height. For example, there's a gimmick in Desolate Twilight Zone where Sonic can access floating island with speed thok (easy method) or spindash (difficult one). But for Knuckles it's not possible. You can play the video slower using HTML5 video player to see what I actually mean.
It's not really a bug, but... I'm not sure if it is meant to be as is.

Youtube link: https://www.youtube.com/watch?v=4JTS4zqyNFY

The Whirlwind jump is just as high as the character's regular jump. So for Knuckles it's lower by the same proportion than his regular jump height.

I've read this article in the SRB2 Wiki before, so that is why I have started this topic. There's a statement which says "boosting player's maximum jump height to 224", which is not true for Knuckles or any other custom skin with different jump height. I think there should be said that player can just do a second jump.
Anyway, thanks for your reply! ^^