I think enough evidence exists to say it was never a consistent collected work of fixed waza in the first place. There was also some insider gossip about the creation of the scrolls that speak to the reasons behind a...uhm...rather fluid curriculum.
I put no stock in the notion of DR either being a fixed art or an old one, prior to Takeda. I suspect it was always him expressing a body method, and certain people recording how the various people responded (in different areas) to what happened when people attacked him. Hence, never repeating a waza.
I recall reading that Takeda charged per technique. When Takeda paid Ueshiba a visit in Ayabe he claimed to be after the money that was owed him for the techniques that Ueshiba taught his students.
Its from this information that I get my idea that Takeda at some point grabbed some students and devised a marketable technical syllabus.
But it could certainly be the case that he just demonstrated principals extemporaneously, and his students codified a syllabus out of that.