I don't use the box settings for exactly that reason. The white level at 25 is almost 100%..so if you raise it by more than 2 all that can happen is more and more grey level turn to white. It's ok for reducing contrast.
I set up my TV using my primary source...my Sat box. It has no video controls...it has to be done via the TV. Once the TV is setup that way I find all other sources (which might have their own video controls) work correctly at the default settings.
To get correct black and white levels, I had to raise brightness by 3 clicks (which almost raised it too high) and lower the contrast by 4 clicks. This was when viewing on a display calibrated to THX levels. The old theory on white levels not going above 235 has gone out the window now. You raise white levels until just before they clip the white with no visible colour shift and no eye fatigue...on a projector this should not read over 16ft lb at 100% stimulus - but on my Mitsibushi, I'm lucky if I get 6 foot lamberts but the picture is still very watchable.
The point of this post is this - if you have calibrated your display using one of the test discs or any other known method, the mede8er settings out of the box are not the same as the calibrated display and need to be alterted. Both my 400 and 500X2's crushed black to no existent - but I didn't know because my display had never been set correctly before...I thought it had, but I was wrong.