The SS-FNO-IP-EOM-CCSD*/unc-6-311++g** method shows a higher error when applied to the Illas test set compared to the Cheng test set. The MAD (maximum absolute deviation) value for IP values in the Illas test set is 1.35 eV, almost double that of the Cheng test set. However, the root mean square deviation (RMSD) error for the Illas set is 0.39 eV, similar to the Cheng set. Nonetheless, the SS-FNO-IP-EOM-CCSD* method demonstrates significant improvement over IP-EOM-DLPNO-CCSD results, which have a MAD and RMSD error of 2.21 eV and 1.36 eV, respectively, even with the use of extra tight threshold in the DLPNO implementation . When SFX2C correction is applied in the SS-FNO-IP-EOM-CCSD* method for the Illas test set, a blueshift is observed with respect to the non-relativistic core IP values. The MAD and RMSD errors in the SFX2C-SS-FNO-IP-EOM-CCSD* method increase to 1.65 eV and 0.50 eV, respectively, relative to the experimental results. It is consistent with the trend observed in the Cheng test set.