Yeah, it's confusing - Elayne's comment, notably, if it's really reliable given her limited knowledge. I was hoping other notes clarified that and it would find its way in the Enccylopedia, but it seems to be one of those things RJ kept vague enough he could do what he want with, and didn't feel any need to write in details somewhere. I supposed greater strength is only one factor that differentiate angreal and san'angreal, but we'll never know for sure.
It's like the formulas for the circles. We know it's not purely additive, but the exact calculations don't seem to have appeared in the notes. We can surmise RJ knew he didn't need more precision than that to write the story.
For sure he was more "economical" than many believe. I suspect from having seen some of the material that Harriet was a bit disingenuous when she said the notes were larger than the whole series. Sure.. in word count maybe it's true, but what I suspect she didn't say is that she counted everything, meaning all existing versions of every document in RJ's files and computer. E.g.: he could have a 30-page "work file" that in fact featured 10 pages of quotes from the books he needed at hand, 10 pages of info from other documents collected in that place for a purpose, and 10 pages of various reminders that in fact offered little new information (it all seemed aimed at ensuring continuity, little more). That same document might have existed in one version per book or per two books. It's easy enough to imagine that together all those files made up more pages than the whole series, but as we can see from the Companion, not a whole lot new information was in those notes. They were in a large part (at the library, anyway, but the Companion suggests it's the case with what wasn't there either) work-documents, to simplify his writing without having to search in a ton of older or more focused documents, like his "central listing" of all AS. So for a storyline or important character, he kept an up-to-date (more or less) file, with physical description, reminders of some opinions, reminders of what the character knew or not (incl. mostly very obvious things, and more "older" things than new as if RJ had done this more early on and stopped later, just carrying the older pointers from previous versions without adding new ones) and that sort of things. There weren't notes (or very rarely) in those files about what was coming in the future for that character (I suspect RJ had a limited amount of those, in other files about the book he was currently writing, and he didn't like mixing that with reference information he used as he wrote). Usually, those documents also listed, with basic information, the secondary characters the main one might meet in the current storyline, so Rand's file would list his sworn AS, Asha'man, Cadsuane's group, that sort of things. Another file was for Cadsuane's group, and a whole lot of it was a copy/paste from Rand's current document. The KOD era files all began with the same long paragraph he had written about the general mood and styles of supernatural events that should occur in the book.
It's fascinating, to observe how he worked but as a treasure chest of unpublished goodies, it was disappointing.
Two areas were particularly disappointing. Except for rare cases (such as a good explanation of the "progroms", there wasn't much in term of explanations of past events or back story. We were lucky to find one or two "revelations" that a character was responsible for this or that. He also rarely felt a need to put down in writing motivations, and when he did it concerned mostly interpersonal affairs rather than politics and such (of course when it was Rand or Egwene that line was a bit blurred anyway, but there really wasn't much that isn't already obvious from the books).
The second area was that of world building/geography/history. Most of what RJ had either went into the BWB or else was written especially for the BWB and then was included in the notes (I tend to think the latter, mostly, since the notes are full of direct quotes from the BWB - including its description of Tar Valon/WT). Basically, RJ made his stuff up as he required for the story, then he added the new things to the notes. So in the end it's pretty much like the books themselves... a great deal more details about Andor, Altara - virtually all of them in the books or the BWB, and much less about the nations we didn't heavily visited.
We saw more on Seanchan, a few more details on Sea Folk culture, but globally we already knew most of that information. Almost nothing we don't know about the AOL (that too was all in the BWB).
I suspect a very great deal if not the majority of the notes consists of sketches and diagrams, of the various drafts of the books too. That Harriet has kept completely under wrap (except for a vague sort of synopsis for the TGH/TDR that is at the library), and for the time being I suppose it will remain that way as RJ hated to show ongoing writings, even to Harriet herself. This will likely join the collection only after her death, or be accessible only to scholars, if RJ's work attract any.
But for certain RJ wasn't the Tolkien type, obsessed with his own world building to the point he half believed it real. He was a great deal more pragmatic, and didn't lose time crafting whole aspects of his world he might not in the end need. He rather seemed to like to create the details along the way. We'll never get for instance the details about Norla and her apparatus, because RJ was filling the gaps as he went along (but I do tend to think he was keeping that and the story of Mariam etc. in reserve for the breaking of Semirhage and Cadsuane's exile).
Some of the more interesting tidbits in the notes hinted at options RJ was contemplating. For instance it's obvious that for KOD or for AMOL, he was toying with the idea of giving us a clue about what happened to Verin. In the file listing Kinswomen, he had for some a few extra bits about their past, and for quite a few of them he duplicated the same note that they had been a novice under Verin and could have witnessed something she didn't understand. It's all very vague, but it seems he had an idea in the back of his mind to have one mention something puzzling at some point, but didn't know yet how that scene might go, or who it might involve.