Neither the UK IET nor the American IEEE use that format. NASA's own website doesn't insert dots on most, if not all, of the uses of "NASA".
I don't understand why there are two formats for indicating contractions. Perhaps the suffix dot indicates a general contraction, while the apostrophe is missing letters in that place, but that rule would not rule out "M'r".
Okay, so I picked a bad example in haste. I'm sure I have seen examples of what I said (but perhaps they were from past times), just I am sure I was told I needed a second dose of the shingles jab after 6 to 9 months, but yesterday (when I tried to book) I was told that should have been two months!
I can see some sense in this, because of pronouncing "Nato" as an acronym rather than "N.A.T.O." as an initialism. With the dots routinely left out of even initialisms, how else would one know how to say it? Not that I am advocating this.
I was told I need mine after 6 months. I've even seen entries in my medical record. First jab - December 2024. In the entry - "Recall 6-12 Months Shingrix booster (06 Jun 2025)".
In the case of Mister - the dot would indicate (to me, in British English) that there is something more to come, eg. Misterxyz , but doesn't show that "iste" has vanished. "M'r" correctly indicates missing letters. It was always my belief, perhaps wrongly, that this was the difference between the two ways of indicating contraction. Mr doesn't indicate the missing letters at all, but is my preferred version.
Normally 6 to 12 months is recommended. Less than 6 months may be appropriate for individuals with some other medical conditions.
I was still confused by why we have Mrs when Missus does not contain a r until I did a search.
An R?
Yes as in head of the household rather than dominatrix or "bit on the side"