Dear Donald, Your article again highlighted the obvious (in hindsight). I thought of a story my father always told: There was a man that believed that he was a grain of corn, which is staple food for chickens. As such he was dead scared of any chickens. He went for some psychological treatment and eventually the psychologist convinced him that he is not a grain of corn and does not need to be scared of chickens. As a final test they asked him to go into a room where they placed some chickens. He scarcely went into the room when he came back sweating and really scared. He looked at the Psychologist and said: "I know I am not a grain of corn, but do the chickens know it?" Do you find that you can convince Companies of the problem with measuring in silos? Kind Regards Francois