Mean errors 1 kcal/mol can be achieved for the S66 complexes using SAPT0 + δHF in conjunction with a basis sets up to jul-cc-pVQZ but the outliers grow larger as the basis-set quality improves. These outliers correspond to dispersion-dominated systems such as the π-stacked uracil dimer and other π-π systems including uracil-benzene and uracil-pyridine, whose total interaction energies are relatively large by the standards of small, dispersion-dominated complexes. Interestingly, the importance of the δHF correction diminishes in larger basis sets, and starting with jul-cc-pVTZ both the MAE and the maximum error are smaller for SAPT0 (sans δE HF ) than for SAPT0 + δHF. This behavior has not been recognized in previous comprehensive tests of wavefunction-based SAPT, because in those studies the δHF correction is always included with SAPT0.