I worked on a simulator back in the day that had two rooms for documentation. One for the official books provided by manufacturer and various subcontractors, and one for the as built/as modified/as hacked to make work late at night.
The official books were written after the 1st unit was built, and all subsequent units were supposed to be built based off of those books. As we know, that is not what happens.
As we found discrepancies, we copied the page out of the official book, made appropriate notes, and inserted into our "as built" books. It made for interesting troubleshooting sometimes when you had to trace a circuit through several pages of several books and then add in the unofficial changes also.