We find that the parameters from AMBER ff99SB generally overestimate QM energetic barriers for these phosphorylated systems, consistent with what was observed in the parameterization of AMBER-FB15. The FB18 parameters adjust these barriers to overall better agreement with the QM data, which we believe can lead to further improvement in the prediction of experimental observables. Indeed, we find that FB18 is able to significantly enhance force field predictions for quantities such as 3 J NMR couplings in these systems, which is particularly promising as the force field was not explicitly parameterized to any experimental data of this nature. Moreover, comparisons between AMBER ff99SB and FB18 indicate that the latter yields improvements in the qualitative predictions from MD simulations with respect to experimental data on phosphate group-to-backbone hydrogen bonding.