There could be various choices for the dispersionless functional, which creates some ambiguity. One might use the dlDF functional that was described in Section 3.2.1, although that seems not to have been tested. Instead, we follow literature recommendations, which suggest using Hartree-Fock (HF) exchange (without correlation) to compute the dispersionless value of ∆E FRZ when a hybrid functional is the target (PBE0+D3 in Fig. ). The dispersion energy estimated using Eq. ( ) also contains any differences in how electrostatics and Pauli repulsion are described at these two levels of theory (PBE0+D3 versus HF), including any correlation effects in E elst and E exch . Other comparisons between SAPT and DFT-based EDA schemes suggest that correlation reduces E exch , an effect that may mimic dispersion. Whatever the reason, the aforementioned ALMO-EDA2 prescription for E disp overshoots the SAPT2+(3) benchmark for every single S22 dimer [Fig. (b)], with a MAE of 14.0 kcal/mol or 209%. The extent of this overestimation gives pause, and causes us to reconsider the choice of dispersionless functional. To prevent correlation effects in E elst + E exch from contributing to E disp , we consider using the HF-PBE functional,