After 15 years of doing the "real" work on this, I find that the Arrhenius equation is only a vague approximation due to a number of factors. The film, the developers, the ratio, the pH, the temperature ad nauseum....

All of these tend to distort the original assumption. And, they just don't always work. I have applied (or tried to) over 32 years and found exceptions in every case. Sorry.