Paesani and co-workers have suggested DFT-based MBE(n) as a tool for generating "data-driven" classical force fields, and reasonable results have been obtained for neat liquid water and for ion-water interactions using DC-SCAN. In our view, this approach has succeeded by limiting the expansion to three-body terms, using a classical polarization model to replace ab initio four-body interactions, and incorporating conservative distance cutoffs. The generality of this approach is questionable, however, in view of the results presented above. Although four-body terms appear to be sufficient for both neat water and monovalent ion-water interactions, 147 higher-order interactions are sizable in divalent ion-water clusters. Our results do suggest there is a "sweet spot" where just enough neighbors are included for accuracy but not so many as to cause significant accumulation of delocalization error; this is exemplified by PBE results in Fig. . However, this may not be sufficient to salvage all ion-water interactions, or for water-solute interactions involving larger, asymmetric solute molecules. A safer strategy is to retreat to HF theory, leveraging the efficiency of the energy-screened MBE to apply post-HF, correlated wave function models. The BH&H-LYP functional appears to be a satisfactory intermediate workaround.