(top panel) NH₃ BEs on a first tested binding site for a growing ΔR_LowLevel, going from 3 to 11 Å, for a total radius between 11 and 19 Å. 4 different basis set for the high-level treatment are tested, as given in the legend of the plot, within an ONIOM(B3LYP-D3(BJ)/basis set:xtb) framework; (middle panel) Relative BE difference with respect to BE at ΔR_LowLevel equal to 11 Å, each series being treated independently; and (bottom panel) Relative BE discrepancies relative to BE at B3LYP-D3(BJ)/aug-cc-pVTZ high level of theory, with ΔR_LowLevel equal to 11 Å.