The bottom line, hinted at in previous threads on Rodinal, seems to be that no one really knows exactly how to make it except the original factory line workers.
Having tried to make it, I find that Rodinal is not simple. If you are just a tad off, things are not the same, and there are so many opinions as to formula and methodology, that even with the right formula staring you in the face, it may just not be the same.
Kodak had problems making developers and emulsions all over the world, and we had to establish internal quality groups to insure that a production batch in Rochester was equal to a production batch in Chalon France or Harrow England. These were all good people, working hard, but things are not always the same with chemical formulas.
That is why so many well meaning and good people here, good photographers all, differ in opinion so often, and why I say "Use what works for you".
So, if you get ISO 400 with 10' and before it was 8', that is a new 'fact of life' but someone else may find that 10' is right now for them. It is odd, but it is the interface between photography, chemistry, and life.
PE