On the generation series you sometimes have to lower it one more notch because the RWD tech drive
tends to lift the front of the machine up just enough for it to detach itself from the carpet.
Are you missing any seals?
my Legend II was missing the nozle seal ring and that caused a huge performance lose, also the rug plate seal would cause a performance lose too.
If the brushroll is adjusted too low that could also cause it to not lock down to the carpet.
