As far as I know there is no such thing as a Class 0 Org. Orgs are Class V (used to be Class iV). This means they can deliver auditor training up to Class V auditor and can deliver auditing up to Clear. But when someone is ready to attest to Clear they have to be sent to an Advanced Org. That is the way it was in the 1990s when I was in. Missions could deliver minor courses and auditing, Class V Orgs deliver services up to Class V/Clear and Advanced Orgs deliver higher levels of training and auditing. Missions and orgs are usually manned by contracted staff whereas Advanced Orgs are manned by Sea Org personnel.
I don't know about that OEC vol. 0 reference. Maybe it made sense at the time it was written but not now. If it was from the old/original OEC volumes then it may not have been written by Hubbard even though his name is on it.
That's how I remember it from the 1990s too. There is also an org called a "St. Hill" org, which delivers the Saint Hill Special Briefing Course (Class VI course) and, I think, Power Processing and Power Plus (Grades V and VA) and maybe R6EW and the Clearing Course. It's possible that the Power and Power Plus, R6EW and the Clearing Course are delivered at Advanced Orgs rather than St. Hills. Perhaps someone will know (if it matters!). Some St. Hill orgs are combined with Advanced Orgs, to form an AOSH (e.g. AOSH UK), but some St. Hills are separate (e.g. Saint Hill Foundation, which shares the same physical location as AOSH UK, but is an SH (whilst not simultaneously being an AO), and the American SH Organisation ASHO (does it still exist?). My impression was that AOs could delivery any auditing up to OTV, but didn't usually deliver the briefing course unless they were also a SH.
I used to be confused about some of the classifications of the auditing levels. For example, in some places the Class VII course was described as the 'internship' for the Class VI course, but according to the Bridge that didn't seem to be true, as the Class VI course had its own internship on the Bridge chart, and the Class VII course taught one how to audit Power and Power Plus (which makes it NOT a Class VI internship, as the Class VI course doesn't cover Power, but does cover pretty much everything else). I also knew someone with an old Class VI certificate, which WASN'T the briefing course, but seemed to be more like what is now called the Class V Graduate Course, or something like that. So presumably the levels classifications changed at some point. I would guess that the SHSBC was not originally called the Class VI course, based on the above.
Going off on a (slightly related) tangent, does anyone know why the OT levels from IX onwards are all called 'New' OT levels? I can understand why OT I, IV, V, VI, VII were re-named as new (because they were replaced). OTII and III are not called 'new', because they are still the original versions. But then why are OTVIII onwards described as 'new'? This implies there was an old OTVIII and IX, but I don't think there ever was. Or did they just decide that any OT level that would be issued after New OTVIII would be arbitrarily also called new?
Not that any of the above matters, but just curious....
W.