Attack Speed Reference

Sommersault Kick/Corkscrew Blow (spamming; no enemies)
Faster (3): 720ms (-120ms)

Corkscrew Blow (spamming; enemies)
All: 1530ms

Corkscrew Blow delay
Faster (3): 690ms (-150ms)

^This is the delay before using another CSB?

You're using a Fast (5) Knuckle with Booster.

You use CSB and it hits nothing. It does the little CSB animation (690ms). You're unable to use CSB again until 720ms have passed, though, so there is 30ms where you can use another attack, like Flash Fists, but CSB is still cooling down.

You use CSB on a mob. It does the WHACK noise, monsters get pushed back, and it takes 690ms. You cannot use CSB again until 1530ms have passed. You can SSK, you can Dragon Strike, you can Energy Blast, or whatever, but you cannot CSB until 1530-690=840ms have passed.