TD-SRC1-r1 errors are much smaller than those obtained using TD-B3LYP or TD-CAM-B3LYP, and not uniform in sign. The former was parameterized to reproduce K-edge transition energies of this sort, and this results in near-perfect cancelation of SIE (which tends toward underestimation of the excitation energy) and missing orbital relaxation (which reduces the excitation energy). The 52%:48% ratio of orbital relaxation to SIE, reported in Ref. 60 for TD-SRC1 calculations of core-level excitation energies, neatly encapsulates the balancing act between these competing sources of error.