Figure (a) and 4(b) show the distribution of the virtual space size and accuracy for the corrected SS-FNO-IP-EOM-CCSD* and FNO-IP-EOM-CCSD* methods, respectively, using a 10 -4 threshold for the Cheng test set. It can be seen that the standard FNO method selects less than 30% of the virtual space. The SS-FNO approach selects almost similar virtual space with a single outlier, which selects around 40% of the virtual space. Figure (a) shows that a similar percentage (not identical) of truncation of the virtual space is observed in the SS-FNO method for all molecules, regardless of their virtual space size. However, it should be noted that the exact truncation percentage is not identical for all molecules. It can be seen that the error in the SS-FNO approach is much less than that observed in the standard FNO approach. The enhancement in accuracy observed in the SS-FNO basis can be attributed primarily to the inclusion of perturbative correction. This effect is less prominent in the standard FNO counterpart, as mentioned earlier.