Just installed the z110bt with vss, and reverse signal. Everything tests good and vss is seen. Unit is still doing 3d calibration. I notice when I go through an intersection that the map dosent show me going through it until after I am physicly through it. So it seems like it is off just a micro amount. Question is does this get better after 3d calibration is complete, or is this just the way it is? I notice there is an adjust my position option but I haven't tried using this yet. Any ideas?