In our benchmark we find that for thermal contributions for iodine-containing monomers are adequately described using either ωB97X-D3BJ or M06-2X with the aug-cc-pVTZ-PP basis set yielding mean absolute errors (MAE) of 0.23 and 0.14 kcal/mol, respectively. We confirm the result of previous studies that the spin-orbit-coupling (SOC) stabilization energy of iodous acids is significant and find that ωB97X-D3BJ with DKH formalism and a aug-cc-pVQZ-DK basis set employing 10 states is a comparatively cheap method for incorporating SOC. Using this method we show the effect of SOC change during dimer formation, where it is observed that there is a significant change of 0.95 kcal/mol in the SOC stabilization energy contribution to the binding free energy with the formation of the iodous acid dimer, leading to an overestimation of the cluster stability if SOC is neglected. This change is hypothesized to grow larger as the valency of iodine increases during cluster growth. This overestimation is also present if the compounds contain higher-valency compounds such as iodic acid, iodine tetroxide, or iodine pentoxide, but it is less significant.