Some of this might be a difference in how people look at the rank divisions. For instance, when I speak of "brown belt material", that's the stuff they have to know to be a brown belt, while you'd be talking about the material learned by a brown belt. I'm pretty sure that's not the distinction in question, but let's consider a middle point between those. Some folks might consider "brown belt" material to be stuff any brown belt should be aware of, so they'd start introducing it before brown, but not focusing on it until they pass the brown belt test. That way even a fresh brown belt isn't starting from square one on that material. This isn't my view, and doesn't appear to be yours, but doesn't seem unreasonable. If you did this at every rank, it would add a small amount of material before the first earned rank (yellow for me, something like chartreuse for you, as far as I can remember
), but would be no significant increase in material after that.