It can be seen that the CBS limits of this work are consistently larger than those of Finney and Peterson, although the difference is small with a mean average of 0.15 kcal mol -1 and the largest deviation occurring for iodine (0.26 kcal mol -1 ). Perhaps more significantly, a comparison of Table V with Table VI highlights that, for the group 13 and 14 elements considered, CCSD(T)-F12b/aVQZ-F12 computes EAs that are beyond the CBS estimates of Finney and Peterson, suggesting the latter are underestimates of the true CBS limit. This adds additional justification for the revised CBS estimates of this work. (Finney) and CCSD(T)-F12b (this work). A total of additive contributions from the FPD composite method (∆FPD) taken from Ref. The combined post-frozen-core CCSD(T) contributions to EAs from the additive FPD approach, previously published by Finney and Peterson (∆FPD), are also reproduced in Table . This includes correlation of outer-core electrons, a correction for using scalar relativistic PPs, higher order correlation effects, QED effects, and SO coupling. These individual contributions are analysed in detail in the work of Finney and Peterson and have been combined into a single value here for convenience. The SO contribution dominates ∆FPD, but it is interesting to note that the improvements to the frozen-core CBS estimates in this work are of the same magnitude as the corrections for using PPs, higher order correlation effects, or QED. In the case of thallium, the difference between the two CBS estimates is greater than the total ∆FPD, but this reflects the fortuitous cancellation of post-frozen-core CCSD(T) effects for the EA of this element.