You only get to take the test for perfecting that skill one time.
I've heard a lot of pretty crazy stories about Morehei, back when I studied Aikido myself. I also saw some pretty crazy things. We had one sensei who used to walk around with a kata stick. He would randomly hand it to new people in the class. He did this to me on my first night (I had no idea what it was all about) and it dropped me to the ground and pinned my hand to the ground. I couldn't get my hand out from under it. It was a very freaky experience. He claimed that he'd loaded it with ki, making it incredibly heavy to those who didn't have strong ki of their own. I watched him do that trick repeatedly throughout the years to people who had no idea what he was doing and it always had that same effect. Wild stuff, even though it sounds like a B.S. story.
jag