For weakly interacting systems, a majority of the pair correlation energies are relatively small such that the pair prescreenings of the DLPNO approach and of the multi-level approach may have severe consequences. Using a target accuracy of TIGHTPNO with the settings given in Tab. SXIII of the Supporting Information, relative energies of 5.2 kJ • mol -1 for phenyl and 146.8 kJ • mol -1 for mesityl meso-substituents were calculated. In both cases, the slipped stacking interactions are therefore relatively underestimated with NORMALPNO settings.