MAEs (Mean absolute errors), as well as boxplots of predicted VEEs by various XC functionals as compared to the reference values, are presented in Fig. and, respectively, where the XC functionals are listed in the X-axis with the increasing order of exact exchange contributions. In the typical case of c MRSF = c SPC = c HF as shown in the top of Fig. , the BH&HLYP and M06-2X, which have c HF = 0.5 and 0.54, exhibit the smallest MAE of 0.379 and 0.358 eV, respectively. Noticeably, the two Coulomb attenuated functionals of CAM-B3LYP and CAMh-B3LYP also exhibit relatively small MAEs of 0.398 and 0.41 eV, respectively. The two CAM functionals have variable exact exchange contributions as a function of distance up to 65% (CAM)and 50% (CAMh) in the asymptotic region. Generally, the MAEs of other XC functionals are increasing, as c HF is either smaller than 0.19 or higher than 0.5. A similar trend of MAEs was also seen in the case of LR-TDDFT. In order to investigate the effect of "Adaptive Exact Exchange (AEE)", a special setting of c MRSF = c SPC = 0.5, which mimics the BH&HLYP functional, is designed regardless of c HF . As a result, while the SCF part is performed with the regular XC functionals, the BH&HLYP is utilized for the response part of computations. Remarkably, dramatic reductions (factor of two) of MAEs are achieved in all XC functionals (see bottom of Fig. ). The XC functionals with c HF ∼ 0.2 such as B97, B3LYP, B3PW91, X3LYP, APF, and PBE0 are especially well improved, making their MAEs smaller than that of full BH&HLYP. The smallest MAE of 0.24 eV is achieved by the CAMh-B3LYP. The statistical analysis in the form of boxplots on the same data is shown in Fig. , where the improved median and reduction of IQR range are also seen from all XC functionals. For example, the -0.35 (median) and 0.68 (IQR) eV of B3LYP are reduced to -0.16 and 0.39 eV, respectively. In short, the statistical analysis revealed the dramatic impact of AEE on the accuracy of VEE predictions. Especially, it is remarkable to observe that the prediction accuracy of all functionals is improved by the fixed value of c MRSF = c SPC = 0.5, which shall be further investigated in the subsequent sections.