Early versions of XSAPT used ChElPG embedding charges for the XPol procedure. These are designed to approximate the molecular electrostatic potential and seem fit to purpose, but engender significant computational overhead (Fig. ). CM5 charges, 120 in contrast, are designed only to reproduce only the molecular dipole moment but can be evaluated much more efficiently using DFT quadrature grids. Although implemented for reasons of efficiency, CM5 embedding charges also turn out to improve the accuracy, especially for complexes involving ions and ion pairs, for which ChElPG embedding charges afford errors up to 15 kcal/mol that are reduced to < 4 kcal/mol using CM5 charges. Table provides an accuracy assessment for XSAPT + δHF + ai D3 and XSAPT + δHF + MBD calculations on ion-molecule complexes, using the AHB21 and CHB6 data sets 172 that consist of anions and cations, respectively. For AHB21, the benchmarks range up to |E int | = 66 kcal/mol and ten of the 21 dimers have absolute interaction energies larger than 20 kcal/mol. (For comparison, |E int | < 20 kcal/mol for all of the S66 dimers.) For CHB6, the benchmarks range from -20 kcal/mol to -39 kcal/mol. As such, these are more challenging tests and errors are correspondingly larger than what we have come to expect for neutral complexes.