Figure presents the error distribution plot of SS-FNO-IP-EOM-CCSD* results for the Cheng test set in the aug-cc-pCVQZ basis set with respect to the canonical reference. The corresponding statistical parameters are provided in the Table . The accuracy of the SS-FNO-IP-EOM-CCSD* method improves significantly when the excited FNO threshold is increased from 10 -4 to 10 -4.5 . The difference in accuracy is clearly seen when comparing the Maximum Absolute Deviation (MAD) between the thresholds of 10 -4 and 10 -4.5 . When the threshold is set at , the MAD is found to be 0.501 eV. However, the MAD shows a significant improvement to 0.253 eV when the threshold is increased slightly to 10 -4.5 . Going even further to a threshold of 10 -5 or higher does not result in any significant change in the MAD value. When the SS-FNO threshold is set to 10 - 4.5 , the mean error (ME) is found to be -0.181 eV. Although there is some additional improvement in the results with thresholds of 10 -5 and 10 -5.5 , the difference is not as pronounced as the improvement seen when increasing from lower threshold values. Substantial improvements are observed in the SS-FNO-IP-EOM-CCSD* results by incorporating perturbative correction. The ADC (2) corrected SS-FNO-IP-EOM-CCSD* method shows a MAD of 0.081 eV and ME of 0.000 eV at 10 -4.5 . A similar effect is observed for other statistical parameters, which improves with the perturbative correction. When perturbative correction is applied, the impact of using a tighter threshold on accuracy improvement becomes less noticeable. The addition of the ADC (2) perturbative correction greatly enhances the accuracy of SS-FNO-IP-EOM-CCSD* method. The threshold of 10 -4.5 results in a Maximum absolute deviation (MAD) of 0.081 eV and a mean error (ME) of 0.000 eV. This improvement is also seen in other statistical parameters when the perturbative correction is applied.