[MizunoJoe]

Thanks Joe, I do not think I quite understand "further acceleration can be applied only at PP#1" in 10-19-C. Is this what you mentioned?

I think what HK means in 10-19-C, is that any further acceleration applied at PP#1 has to be a pull along the shaft, because if you push on #1 with the right triceps, you would preempt cf, and be switting. That's the only sense I can make of it.