Super XX 200ASA
Plus X 125ASA
As far as know (I've been wrong more than once) those are the speeds GIVEN by film companies, but yes there was a change in ASA speed at one point. Basically they would rather you OVER expose, than under, and I think that means at one point 100 speed was really 200 speed at today's standards. But I don't know when that cutoff was, and there were different versions of at least plus-x and verichrome so they may have really been 400 and 250 speeds at today's standards.
That's my understanding.
~Stone | Sent w/ iPhone using Tapatalk