Considering the case of a sequential multistep reaction (Eq. 5) with only one-electron transfer steps, we investigated when the net current would behave as in Eq. 20, see SI.M5b. We find that this is only the case when the coverages of all intermediates at the equilibrium potential share the same value (Eq. 21a) and that the stoichiometric products at any potential are equal (Eq. 21b). Only in such case, a sequential multistep reaction can be described by a simple B-V equation with an exchange current density defined by Eq. 21c, and all definitions of the exchange current density are equivalent (Eq. 21d).