In figure we show DLPNO-CCSD(T) energies of the small test set calculated with a range of T CutP N O values for both CBS(2,3) and CBS (3,4). Between these, the trends are mostly the same, with similarly shaped dependence of the REs and BHs on T CutP N O at both levels. The CPS extrapolations generally fit the trends well, with CPS (5,6) in between 10 -6 and 10 -7 and CPS(6,7) lying beyond 10 -7 . In some cases like 4-OT RE1 and HKMT-2 RBH, CPS (5,6) overshoots the TightPNO/10 -7 energy due to the strong inaccuracy of T CutP N O = 10 -5 , similar to CBS(2,3) being affected by the low quality of doubleζ results. CPS(6,7) is more consistent, and generally represents an improvement over standard TightPNO in terms of approximating the tighter T CutP N O = 10 -8 threshold value. As relative energies do not necessarily converge monotonically to the T CutP N O = 0 limit, we also show the convergence of the correlation energies of each structure in this small test set with the T CutP N O values in figure of the Supporting Information. The observed behavior is generally different between CBS(2,3) and CBS (3,4), but this is unlikely to be an issue as Altun et al. have noted that the form of the CPS extrapolation does not depend on the form of the convergence of the correlation energies. From these tested BHs and REs, we have calculated mean (absolute) deviations (MDs and MADs) of the CPS and standard TightPNO results as a rough es- ). A value of 10 -7 is the default for TightPNO. Tightened T CutP N O = 10 -8 results could not be obtained for CBS (3,4) due to the cost of the def2-QZVPP calculations.