likely because the attack / skill uses the same GCD. the time between press and release is what? tenths of a second? You wont be able to notice when its the press action or the release action thats firing. It wont run automatically, (of course). so when you press it once and release, it could still be in the mode of the 21 seconds from the initial press, so the release gets skipped.

So instead of trying to use the same attack / skill, you wouldnt be any better off than if you just did a single step action and just spammed the key.

I.e. the software isnt going to allow you to automate and thus break any ToU.


BTW, good job workin out your different variables.