Has anyone noticed that you can set the altitude for your location (I used a USGS TOPO) for home? If you start close enough to it, it will calibrate for altitude at start, and then the rides are always more accurate. Since I set that parameter in my 800 I typically have about 10 feet delta between climbed and descended; before I set the location of "Home" it could be has many as 100' delta per 20+ mile rides.