DF Tremolo Tuning Stability Issues

I'm having very annoying tuning stability issues with my Fullerton Deluxe S-500. I promise I don't do anything crazy with the wiggle stick, but it doesn't take much at all to end up out of tune by half a semitone or more (typically sharp). Does anyone have any suggestions? My bridge came set up probably half as high as the recommended height I found here:

http://guitarsbyleo.com/FORUM/viewtopic.php?f=13&t=3371

After raising the bridge to the recommended height, I was definitely pleased with how much more smooth the trem operated, but tuning stability didn't improve, and might have actually gotten worse. I used a pencil to get some graphite in the nut slots, but that didn't help either. My bridge is completely level after adjusting the springs, so I don't think I have any issue with spring tension. Does anyone have any recommendations for what else I can try? Thanks!

Take a look at this post in our G&L Knowledgebase forum: Vibrato Tuning Stability - New S-500 Tribute.

If none of these items to check don't fix your problem and you are the original owner and purchased the guitar from a G&L dealer, contact the dealer.
You have a 10 year warranty with your guitar. If the dealer is local and has a tech department, they might be able to find the issue.
If it is not fixable, they would be able to contact G&L and have it sent to the factory for repair under warranty.

Hope this helps. Keep us informed on any progress in getting this resolved.