And this is from an Anybody But Busher.
For those who want my opinion…the documents appear to be done in Word, and then copied repeatedly to make them “fuzzy”. They use features that were not available on office typewriters the 1970s, specifically the combination of proportional spacing with superscript font. The IBM Executive has proportional spacing, but used fixed type bars. The Selectric has changeable type elements, but fixed spacing (some models could be selected at 10 or 12 pitch, but that’s all). The Selectric Composer was not an office typewriter, but apparently did use proportional spacing. These were very expensive machines, used by printing offices, not administrative offices.
Click the link above to see his graphic demonstration.