Gee, I thought I could contribute more to this thread. But, when I reread Barry’s comments I think he has hit the nail on the head. Component tolerances and active component responses have a great deal to with the final response.
I would always suggest building the circuit to stock values first to ensure that it works as advertised. Then try mods one at a time to tweak the pedal.
With your experience with this circuit, you have obviously proven this to be true before. I’ll bet a cold Coors Light beer that the next one you build will perform differently!