The change in tie lines from negatively to positively sloped with decreasing f C can be attributed to the shift from where the TM contributions are dominant to where the RPA contributions are dominant, as the RPA is known to exhibit preferential salt partitioning to the coacervate phase. To quantify this, we define a metric to compare the relative strength of coacervate formation due to the RPA versus the TM contributions to the theory. We choose to not compare the absolute magnitudes of their free energies, as an arbitrary reference free energy could be added rendering any comparison moot. Instead, we choose to compare the thermodynamically relevant second derivative quantities of the free energy contributions, which describes the strength of the driving force for phase separation due to each term in the free energy. We can write the comparison as: