Note that, in practice, there could be several other reasons for lack of scaling between two adsorbates. Relaxation of the surface and site dependence of the adsorbate might cause scatter on simple transition metal surfaces. For that reason one should always consider scaling for a fixed surface structure. However, the adsorbates and surfaces we describe in this work are transition metals with the simplest of mono-atomic adsorbates, with chemisorption energies in the dilute coverage limit. The fact that these simple systems do not scale in an obvious manner shows the complexity associated with surface chemical bond formation. Care must be taken while fitting linear scaling relations for transition metals for more complex reactions and intermediates.