To model cluster growth, we need to add monomers to the (SA) n (base) n clusters. However, we recently identified that the addition free energies were quite erratic for SA-AM clusters. This was concluded to be caused by insufficient sampling. Here we re-calculated the addition free energies for adding 1-2 sulfuric acid molecules to the SA-AM clusters. These addition free energies correspond to the following reactions: The calculated data are presented in Figure . The B97-3c//GFN1-xTB data from our previous work is plotted for a comparison. Compared to our previous work, we see a significant improvement in the form of reduced scatter in the calculated addition free energies. However, despite the significantly improved sampling methodology presented here, we still observe an oscillatory behavior in the SA-AM addition free energies, for clusters with more than 10 acid-base pairs. This can be caused by two reasons. Either the sampling methodology for "flexible" systems is still not accurate enough when we reach larger sizes of 10 or more SA-AM pairs, or when we reach 10 or more SA-AM pairs, the clusters cannot anymore be viewed as individual configurations and the addition free energies should be calculated over an ensemble of configurations.