I'm certainly no expert but there are proportional fonts -- where letters such as "i" take up less horizontal width than "w" but there is also something called "kerning" in which letter shapes are taken into consideration when spacing is done. Under kerning, it is possible for one letter to "intrude" into the horizontal space of another where say an "A" is next to a "W" as in "AW".
I don't know for sure, but I doubt proportional font typewriters would be capable of kerning as they would need to "know" what letter had preceded the one being typed.
Looking at the first memo, it appears that kerning was employed in the word "May" where the tail of the "y" appears to curl beneath the serif on the "a".
Kerry to staff: These freepers know about kerning. You told me no one would know that!