Wow! That's a very fascinating bit of info regarding aligning the IRS after moving the plane to a different gate only 400 feet away Lou.
In FSX/P3D, I often move my aircraft 100's, or 1,000's, of miles from where I last shut them down, and if it was going to be as difficult to realign the IRS, as it was in that real life experience, I would have given up flying the modern airliners, and stuck to GA aircraft, years ago! :o :D