Ian;

Of course something was going on in the old formula. I believe that in one post you mention that the concentrate had to sit for a while after final bottling. There were additions made and then a "hold for ripening" that the Rodinal underwent before sale. IDK what this involved, but I assume it had something to do with pH.

I say again that the adjustment in formulas may have been to track the changes in average emulsions from Agfa, Kodak and Ilford as they had much more surface iodide. This would entail some change in pH and bromide to tweak development and other paramaters.

PE