Nonsense. This is what you'd have to do to reproduce the centered text, exactly.
Type the line on a separate piece of paper. With proportional fonts, even if you had a proportional typewriter, you don't know how long the line is until you type it.
Measure the length within a point (1/72 in.).
Reposition the carriage to the correct place, within a point.
Repeat for each line.
This was a person who does not know how to type, writing a casual memo for is personal record.
For goodness sakes, give the guy a break. He is the expert in this field. For his reputation, he would like to see better documents.
Actually, if I recall correctly, you would have to repostion the paper by visual guesstimate, since the carriage only moved in designated steps. I remember having to do just that on old Selectrics. But why would Killian bother with such a fractional centering detail in a memo to himself, especially since he didn't type at all?