The responses have been very educational. Iím sure everyone is right about the on-line flight reporting services and their lack of accuracy compared to actual flight. In my ignorance I assumed all readings would be close if not the same.
What brought this all to light was my concern for what altitude others were seeing me at in their cockpits. On nice days it can get pretty crowded on the East Coast and although I donít totally rely on it , itís nice to have a second set of electronic eyes watching for traffic. I WILL check it out with ATC on the next flight .