Under normal circumstances, I would think things like you mention would be the case. But, we have statements like this, "Mochizuki trained hard to crush things with his hands, but he never developed a grip like Uyeshiba's."
Let me take a step back. This is the Mochizuki who studied directly under Mifune, Kano, and Ueshiba. This is the Mochizuki who studied Katori Shinto ryu. I don't know who his kendo or karate teachers were. Here's his rank:
10th dan, Meijin Aikido, IMAF
9th dan, jujutsu
8th dan, Iaijutsu
8th dan, Judo
5th dan, Kendo
5th dan, Karate
So, I go back to what is written and find that Mochizuki couldn't replicate Ueshiba's power in his grip even though 1) he experienced it directly and 2) he actively tried.
With that in mind, I think there must be something else in Ueshiba's grip. So, respectfully, I'm disagreeing with your position. If it was a matter of placement, position, etc, then I think a man like Mochizuki would have figured it out. Yet he didn't and he had more experience than most, inside or outside Japan.
If not placement, position, physical strength, then what?