I do recall some controversy of using "m" as a prefix instead of "milli". It was said there were too many issues with m/M and sloppy writing. The whole problem would rear it's head dealing with resistance and troubleshooting circuits and not so much the repair of the same circuit.
In the old days there was no nano, pico, atto, femto, giga, tera, peta, exa.
There was only milli, micro, kilo, mega.
[\quote]I would say there was no NEED for any of those values at that time.