I also use the tweak station to un-tweak the chassis itself. Take the wheels off, clean off any crud on the bottom of the chassis, and put the chassis directly on the station. If you only lightly tighten the top deck screws, you can then straighten the chassis out by twisting it, and then re-tighten the top deck screws.
This is assuming that everything is put together right in the first place and nothing is bent. Fine tuning only.
Also, in order to get an accurate reading on the tweak station, the chassis must first be L/R weight balanced.