I wouldn't cling too tightly to Takahashi's explanation of aiki, and particularly not to his diagrams Like most of Sagawa's students, he didn't get the complete picture. Either that, or he is not divulging it. I tend to go with the former reason, however. Read "Transparent Power" (by Tatsuo Kimura) to understand how and why this could happen.
There are a lot of interesting things in the Takahashi stuff, but I tend to agree - either he missed some things (quite possible) or he's deliberately obscuring some things (also quite possible, knowing how the Sagawa folks operate).
Note that he himself said that Sagawa never explained what the principles themselves were, so what were left with is Takahashi's interpretation, which may or may not accurately reflect what he's actually doing.
Anyway, it's another datapoint.