He is talking about the deep dive specialty, which allows a deeper dive than the AOW deep dive.
I am PADI, not SSI, so I don;t know their rules, but PADI does not require those precautions on the AOW deep dive.
No, it's not a standard.
However, at the local site we use for our AOW deep dives (platform at 100 feet in total darkness after the first few feet), every instructor I've seen, regardless of their agency affiliation, makes some provision for extra gas on that dive, either staging it or carrying it, because the dive can be very discomfiting to students. I'd classify having extra air on this dive as a best practice whose potential benefit I want available for my students--and a practice I never want to be in the position of having to explain why I didn't follow it.