I don't agree with the one commenter who said you should stay away from videos. I think your video was just fine. I learned a lot and the information was clear. Thanks.
I'm not a big fan of Obama, but I wonder if the discrepancy of type could have anything to do with the irregularly worn surface of the typewriter's roller and also the different pressures applied when a key is struck. A good test would be to compare it with another document typed in the same era...
The magic is real, but the audience and the video is not.