Doug: I worked at a research center for a major automobile manufacture. I built numerous proto type vehicles. They had a set of scales built into the floor. I tried telling the big wheel that it wasn't correct. He ask me to prove it so I weighed the car then spun it around. The floor pockets were not level. So I was tasked with leveling everything so it weighed the same, try and see if the readings are identical. Birdtracker