The MUE of PBEh-3c, which is a dispersion-corrected hybrid DFT/double-zeta valence method, is 1.9 kcal/mol which is very similar to the 1.3-2.1 kcal/mol MUE values obtained by Sengupta and Raghavachari 1 for dispersion-corrected DFT functionals using the much larger 6-311++G(3df,2p) basis set and B3LYP/6-311+G(d,p) geometries and frequencies. This is consistent with Sengupta and Raghavachari 1 's observation that the Dev-2 error is fairly insensitive to basis set size. Similarly, the MUE of HF-3c, which is a dispersion-corrected HF/minimal basis set method is 2.4 kcal/mol, which is only 0.3 kcal/mol higher than the value obtained by Sengupta and Raghavachari 1 using HF/6-311++G(3df,2p)//B3LYP/6-311+G(d,p). The MUE is computed without reaction 19, which is a clear outlier and will be discussed in detail in the next subsection. For comparison, the STO-3G MUE is 3.0 kcal/mol, so empirical corrections (most likely dispersion) contribute to accuracy of the HF-3c method.