If I'm not mistaken, the stats plugin should also find all files in hidden folders if you set Show Files to "All". I had guessed that this inconsistency might be due to the SanDisk firmware hiding the MUSIC folder. Now, it looks like stats and the database agree about the number of media files present on your player. You haven't provided any independent confirmation of the actual number of media files on your player at the moment. Why do you expect there to be more than 1600 media files on your player?