As a final note, we observe that second-order perturbation theory is sufficient to connect three monomers. Three-body induction couplings for XPol + SAPT0 have been derived and implemented 33 but only tested in a few cases. Recent three-body benchmarks suggest that the XPol treatment affords an accurate treatment of nonadditive polarization for small-molecule trimers, which is degraded by the inclusion of the three-body induction couplings. 164 This is demonstrated in Fig. , where XSAPT nonadditive induction energies computed without the three-body induction couplings are in reasonable agreement with SAPT(DFT) results where three-body corrections are taken from wavefunction-based SAPT. In contrast, XSAPT induction energies that include the three-body induction couplings are much larger. It is suggested that this overestimation likely results from neglect of the complementary nonadditive exchange-repulsion interactions, 164 which have not been implemented. As such, these three-body induction couplings are not considered further, and they were not included in the many-body EDA scheme described above. See Ref. 37 for a version of this EDA that does include those couplings.