Group additivity needs improvement (Dah)

We should think of how to improve our groups.

Here's an interesting example: H298 of vinoxy radical (C=C[O]) is 18.5 kJ/mol according to the DFT_QCI_thermo library.
If we ask GAV to estimate the thermo of each resonance structure, we get:

H298 = 18.101 kJ/mol
S298 = 264.78 J/(mol*K)
Thermo group additivity estimation: group(Cds-OdCsH) + group(Cs-(Cds-O2d)HHH) + radical(CJC=O)

H298 = -13.3136 kJ/mol
S298 = 251.061 J/(mol*K)
Thermo group additivity estimation: group(O2s-(Cds-Cd)H) + group(Cds-CdsHH) + group(Cds-CdsOsH) + radical(C=COJ)

A very minor deviation for [CH2]C=O, but a significant deviation for C=C[O]. However, since RMG chooses the thermo of most stable resonance structure (lowest H298), we get a very wrong value.

It seems that we're hitting the correct groups for C=C[O]. Also, the radical correction of C=COJ is in accordance to literature (https://doi.org/10.1002/chem.201301381).

We should understand what causes this large deviation.