To ground the performance of MBE(2) for HF-3c in terms of more conventional quantum chemistry, we next examine the performance of various QM models when ∆E int is computed using the ωB97X-V functional, in basis sets ranging from def2-ma-SVP to def2-ma-QZVP. Supersystem calculations at the ωB97X-V/def2-ma-QZVP level exceed our computational resources so instead we examine MBE (2) results that include all residues up to R cut = 8 Å. The resulting interaction energies are provided in Table , comparing ωB97X-V (in various basis sets) to HF-3c. These data come from previous work, 14 where we established that ωB97X-V/def2-ma-SVP predicts stronger interaction energies than HF-3c whereas ωB97X-V with triple-and quadruple-ζ basis sets predicts weaker interactions. We also know that BSSE can be quite large for sizable protein-ligand models, especially in double-ζ basis sets, and convergence of the ωB97X-V interaction energies in Table provides some measure of it. For the largest system considered here (1BOZ), the ωB97X-V/def2-SVP and ωB97X-V/def2-QZVP interaction energies differ by 23 kcal/mol.