Hugh and Gerardo,
You are engaging in Textbook circular reasoning. You believe that everything O Sensei did was based on this notion of in yo ho. Therefore you see Sensei throwing with the fan in one hand and the other dangling as evidence of in yo ho because your approach also calls for the hand to be down to balance the forces in the body. You ignore all the examples when his arms are not as you desire. I understand what is being claimed. I call it dangling to make a point. Beginners always leave an arm dead. I guess you'd say they know the secret of in yo ho.
That O Sensei did a variety of things to fit the situation is not an opinion. You can see this on the videos. He described what he was doing to his students. He gave interviews. He wrote. It's called take Musu aiki.
And you are creating a contradiction where there is none.
Yes, of course O Sensei did different things to fit the situation. But all of those things were driven by the same fundamental principles.
I never had the opportunity to train with O Sensei, but I'll bet the people who did would say that his off-side arm, "dangling" or not, was about as "dead" as a lightning bolt.