Context, context, context is the rule for the Japanese.
Quoting his answer:
I was told "What you guys are doing now isn't real Aikido". That's really a terrible thing for someone who is such a senior to you to say and I really resented it, but I was told, "This is Aikido" by O-Sensei and I have protected that as I continued in my training. I was told "After the war O-Sensei just changed the techniques however he pleased", so I thought "After all, people from before the war are different".
You have to wonder what the context was for Mochizuki's statement. What the context was for Ueshiba's statement. Just what did Ueshiba mean by "This"? And, more importantly, when each was done.
My sense of both statements (and it's just my interpretation) is that they are meant by Tamura to be general commentary rather than comments on specific instances. This is especially true for the statement by Ueshiba - my sense is that Tamura is saying that what Ueshiba showed him in the times he trained with over the years ("this") is what he was trying to preserve.
He didn't mention a time frame.