I guess I'm not seeing what you are seeing flipping back and forth between runs. If I were placing the 500 low I'd be inching it even a bit further west from 06z, at least by the time it gets to Cleveland. The big "win" on the 12z run, however, is that the GFS did juice up the front end. This is all about what we can get before the screaming 850 jet (85kts!) gets us by 00z Monday.