Yeah, well, as a Capt I know how. Much power is required to start my taxi based on what I think I weigh. If it's too much, time for a reweigh. Especially true in cargo ops. To miss by 20,000 lbs. is beyond the scope of my imagination. Maybe the Captain was one of those affirmative action hires from the 80's...Where's 411a when you need him, RIP...