From a reader:

Jonah:
Interesting theory, but…
When I was stationed at Patrick AFB (1971-74), I distinctly recall our office (Office of Public Information) had a correcting IBM proportional typewriter along with our standard-issue Selectrics. Nobody wanted to use the damn thing. It was a pain in the butt to use because to backspace you had to use a table that prescribed the number of “ens” for each letter for both upper and lower case. I believe (but I’m not sure) that the typeface was some form of Times-Roman rather than Courrier.
Before my recollections are questioned, I want to assure you that the AF Good Conduct Medal listed on my DD214 is entirely legitimate.