"If you do "mash the carpet", using kickdown, then it will always hold the current gear until the rev-limiter is reached, and only then change up."
No it doesn't.
If you kickdown, then lift off, it won't redline. It'll change up.
Erm, you are twisting words:
If you press the accelerator pedal fully down, so that you have pressed the kickdown switch, and
hold the pedal there - then the box will change down to the lowest possible gear, and will NOT change up, until the rev-limiter is reached.
However, if you do lift off enough to release the kick-down switch, then of course it will change up earlier than the rev-limiter, and will revert to using the adaptive shift pattern.
These two scenarios are very different!