In the case of the Ar•••H 2 O complex, the Hartree-Fock-based version of propSAPT leads to at most 19% error compared to the CCSD(T) reference, whereas its Kohn-Sham-based variant performs even better with a maximum unsigned relative error of 13%. The performance of the FF-SAPT calculations for this system is very good, especially for the DFT-based approach, where the errors with respect to CCSD(T) were below 3%. For the Hartree-Fock version of the FF-SAPT, the agreement was observed to be within 6%.