FWIW that exercise is not a Ueshiba "invention" or discovery. He got it from Takeda. It's part of the DR in/yo ho breath-power method.
Where did Takeda get it? It's a fairly common procedure and there are many variations (I spotted it without any real effort and I didn't study with Takeda). Ueshiba may well have gotten it from Takeda, but then again he may not have, since Ueshiba obviously got some other things from other people in his life. Let's just leave it at "Ueshiba may
have gotten it from Takeda", since that's the best we can logically do.... if we have to even bring it into the discussion. Again, I can't fathom why you seem compulsively intent on wresting all credit from Ueshiba and giving it to Takeda. Do a little of your "huggin' and making friends" here and just let the old men be.
How about chipping in to the topic? If you understand the standing breathing method, why not describe what's being done, precisely. I'm sure you must be aware that there are some details that haven't been mentioned like how the forces are directed, etc. Why not tell us more about the procedure since it's part of something you studied?