As far as I know, SketchUp does not save the ground altitude from Google Earth (or Google Maps). The snapshot is placed centered on the model origin and the model origin (point) intersects the terrain surface. So there is no way for the query tool to know how to correctly determine the z coordinate of the mported point.
So you need to know the elevation of the model origin (you can get it from Google Earth or other geo tools). The real altitude of a point in SketchUp is its z value (inch) + the altitude of the model origin in Google Earth. Vice versa, if you import a point you would have to subtract the altitude of the model origin.
If you have the geo-locations in kml file format (placemarks in Google Earth), you can use KML Tools which solve the altitude problem automatically.