Gps shows you accuracy around a circle of the location...it doesn't "repeat" in the same place every time like loran does. This normally puts you left, right, above or below the location depending on the satellite locations. Also, I'm not sure if the government has totally turned off selective availibility (S/A). If they have cranked this back up to what it used to be that would make accuracy up to 100 meters in any direction 95% of the time. That would make the error you have. Also, if you have DGPS (differential correction) make sure it is turned on. Down in Florida we have a "zone" where the gps doesn't work at all sometimes. Depending on pinpoint nav with a gps can be very hazardous to your health...our domestic units aren't in the same class as smart bombs. Bill P.