In general, it appears that higher amounts of Fock exchange lower the REs (and thus deviations) for CDO. 3RE4's deviation is smaller for B3LYP-D3(BJ) (20% Fock exchange) than B3LYP*-D3(BJ) (15%), and it is no longer the maximum deviation for BHLYP-D4 (50%). For the Minnesota functionals, 3RE4 and 5RE1 also stand out for M06-D4 (27%), but not M062X-D4 (54%); the latter also has the largest negative deviation for 3RE1. The same is also seen for the double hybrids, with only three of the ten shown in fig. not having CDO 3RE4 as their largest positive deviation: SOS0-PBE0-2-D3(BJ) (79.37%), B2K-PLYP-D3(BJ) (72%), and the range separated functional ωB2GP-PLYP (65-100%). Instead, these three have their largest deviations for REs from the copper-dependent enzyme Hcas mentioned earlier, MP2 is particularly problematic for copper enzymes, and the PDs of MP2 itself for the two triplet Hc REs are 658.9% and 607.5% respectively. 1RE2, which was particularly sensitive to MP2 in the reference value tests in the Given that some systems seem more sensitive to the choice of functional than others, the DFAs have been additionally assessed on each reaction, using mean absolute PDs (MAPDs) for a more fair comparison between them. The full analysis can be found in section 4.3 in the SI, but here we briefly summarize the results of table , which lists the top ten methods for each reaction. The best five DFAs on overall MAPDs are revDOD-PBEP86-D4 (30.6%), ωB97M-V (32.4%), SOS0-PBE0-2-D3(BJ) (32.7%), MPW1B95-D3(BJ) (33.1%) and ωB97X-V (33.1%). At least two of these (or their variants with other dispersion corrections) can be found in the top ten list for each enzyme, with the ωB97X functionals appearing most frequently in the top ten (8 out of 10 systems) and SOS0-PBE0-2[-D3(BJ)] appearing most frequently in the top three (5 systems, in the top ten for 7). This set of five DFAs thus provides a good starting point for finding a functional for a given metalloenzyme, as at least one should give a reasonable result. While we have noted that MP2 causes issues for Hc, the double hybrid PBE0-DH is actually its best functional; PWPB95 is second best, suggesting that this system does benefit from the use of fifth rung functionals as long as only a small amount of MP2 correlation is included. PWPB95's good performance for transition metals and organometallic compounds has also been observed elsewhere. PBE0-DH is also third best for Mo-Cu CODH, so we also include this as a specific recommendation for copper de-pendent enzymes.