2 of the 3 American Standard Cadet 3 toilet bases I purchased recently have a protruding horizontal ridge across the bottom that allows the toilet to rock back and forth lengthwise. The one that doesn't rock has the horizontal ridge but it doesn't protrude beyond the rest of the base, so the toilet base can contact the floor normally. I am considering grinding the horizontal ridges down so the toilets contact the floor completely without rocking but am concerned about structural damage and warranty issues. And I shouldn't have to use shims and caulk on a perfectly level floor. Design flaw or bad quality control? Either way, bad form by Am Std!!