One thing is certain it is an official document so it's veracity is not in question.
I admire your faith in the OEMs of the world.
Your comment doesn't necessarily follow as day follows night ... over the years I have referred a variety of OEM Manual errors back to the relevant OEM for subsequent correction. Indeed, I have picked up a number of Regulator errors in Flight Manuals and referred them back to the source for correction - the fact is that none of us is incapable of error ... doesn't matter for whom one works.
Some of the assumptions in your argument may be incorrect.
While errors are always a possibility for any of us, Gysbreght has a great many runs on the board .. I'd err on the side of presuming him to be correct until proven wrong. On this point, Owain Glyndwr (another with many runs to his credit) agrees.