For a given pair of thresholds T CutDO and T CutPNO , the DLPNO errors are larger at the CCSD(T 0 ) level than they are at the RI-MP2 level. The most likely explanation is the additional approximations that go into DLPNO-CCSD(T), namely, a perturbative treatment of the weak pairs, 7 whereas DLPNO-MP2 calculations simply involve truncation of the orbital space. Whatever the reason, DLPNO-CCSD(T 0 ) calculations exhibit outliers up to 1.3 kcal/mol when using loose thresholds but all of these errors are reduced below 0.8 kcal/mol for the normal CCSD(T) thresholds, and below 0.3 kcal/mol for tight CCSD(T) thresholds. Meanwhile, even for the loose thresholds the average error is < 0.3 kcal/mol. However, these data do suggest that DLPNO errors are smaller Absolute DLPNO errors for (a) CCSD(T0)/cc-pVDZ and (b) RI-MP2/cc-pVDZ interaction energies, for the S66 complexes. In both cases, the PNO thresholds are the CCSD(T) ones from Table .