Analysis of the gas-phase energetics reveals a systematic overestimation of ion-pair formation energies at the M06-2X/TZVP level compared to MP2 calculations, Method dependence extends further up the hierarchy of methods, with MP2 also overestimating energies relative to CCSD(T), though the magnitude of this overestimation is smaller. Specifically, for MAO sheets with n = 5-8, the average difference between MP2 and CCSD(T) energies is 6.9 kJ mol -1 , while M06-2X deviates from MP2 by an average of 16.1 kJ mol -1 . However, the substantial standard deviation in the M06-2X/MP2 energy differences (10.8 kJ mol -1 ) is comparable to the mean itself, precluding the identification of reliable size-dependent trends in ion-pair formation energetics.