I guess it's what happens when one has been a consultant for twenty five years. testing the reasonableness of data becomes second nature. Perhaps it's the difference between consultants and accountants {snerk}. My employer once got my tax deduction wrong by a factor of three or so. I worked out that it was clearly wrong by approximation in ten seconds. It took the office accountant fifteen minutes to convince himself that I was right because he couldn't accept it until he had worked the correct answer out to the exact penny.