Hi 
The Maths Guide is getting a major re-vamp fairly soon. The Docs Team suddenly found the German translation had added tons of extra stuff and even has enough to break it out into separate chapters. If you can read German look for their version.
My guess is that your case worked out all right and in the guide they might have had a previous example at some point in the last 10 years or so that maybe didn't make it into the version of the guide you are reading. Also when creating the guides sometimes weird things do happen and there are never enough people in the team to get everything perfect.
MS Guides only need to be produced to cover 1 release every 3 or 4 years and they employ tons of people to work on those guides. Their guides cost quite a lot too so that they can pay people and make a hefty profit. LibreOffice has a major new branch twice per year and relies on people volunteering and in the few places where they sell it the prices are extremely low. Even so most people just download the free versions from the official website or the wiki. So, "it's a completely different bottle of crisps".
The Draw and Impress Guides recently got taken on by someone that really cares about them so quality has jumped up in the last couple of releases but Math is still a bit iffy, at least until the translations from German get done. Personally i am hoping the Docs Team are focusing on the Base Guide this time and maybe worry about Math afterwards but people join the team to work on issues that concern them and so that's what gets the most attention. It works well because it means the people working on any particular guide have a vested interested and are keen to get good quality results.
Regards from
Tom 