To address the spread of values in the fitted parameters, we note that the transfer coefficient itself may be a function of the applied potential as predicted by Marcus theory, because at negative potential, the transition state is more initial-state like (𝛽 =>? ~ 0) and at positive potential the transition state is more final-state like (𝛽 =>? ~ 1). However, Marcus inversion is not expected to be significant over the relatively small potential ranges studied experimentally, and all of the studies used were performed with nearly identical potential ranges.