Problems with accelerometer after calibrating.

I've got a Galaxy S which was working fine when I bought it a little over a month ago.  Recently I downloaded a couple leveling apps (Clinometer and bubble).  After trying them I found the calibration was off just a little.  So I then performed the "horizontal calibration" in the display settings.  After doing so the calibration got all screwed up...

.. now when the phone is level, all 'looks' good.  Calibration at first glance is right on.  The problem is the scaling is now off.  If I tip the phone up to a 90deg angle the clinometer displays only 30deg (tried two different apps).  This is NOT an app problem because its also causing problems with auto rotating the screen.  I have to really hold the phone straight up now to get it to rotate. 

Ideas?  any way to get the default back?

Thanks!

Thanks.  So far that seems to be the only option. I was hoping to save myself the trip to the store and the hour wait. I guess I was hoping to delete or update some calibration file somewhere.

Thanks Casz.  I think I'm going to try it.  Doesn't anyone happen to know if there is a .conf file for this somewhere on the file system?  I've looked in the /etc folder but didn't find anything.  I did see a /dev/accel folder but I haven't rooted the phone so no priv to open it.  There has to be a .conf file somewhere?  If I don't get anywhere I'll end up trying the reset.

Update...

... well I brought the phone back to the store and they did their reset ( I get the feeling they just did the same reset I did).  Still the problem existed.  We loaded a few leveling/clinometer apps on a store demo and I showed the difference (theirs went to 90deg, mine only to 30deg).  The tech came out and saw and shrugged his shoulders as if to say so what.  After explaining its a hardware problem and it really is affecting everything they decided to order me a new one. 

    So my question now is whether this is a common problem.  I don't see anyone else having this problem.  I wouldn't want to get a new phone and do the same thing again. 

     Can someone out there test this for me?

1:  Download a leveling app (ex Clinometer, or bubble level)
2:  Running the app stand the phone up on its side (90deg) and see if its reading correctly
3:  Perform a calibration (Settings -> display -> Horizontal calibration), just put the phone flat on a table and click "calibrate"
4:  Now run one of the leveling apps again and see if it still goes to 90deg.