For both of the large systems examined in this section, inclusion of the δE HF correction worsens the agreement with the benchmarks. Reasons for this are unclear. In small-molecule benchmarks, δE HF has its most important effects on hydrogen-bonded systems whereas this correction is negligible for dispersion-dominated systems. Although neither (coronene) 2 nor the DNA intercalation complex involves hydrogen bonding, the correction is 2-3 kcal/mol (and therefore not negligible) in these large systems. It is worth noting the hybrid nature of the δE HF correction in XSAPT: E