We investigate the errors of the QM/MM-PHVA approach by comparing it to full QM calculations on the small model systems. For these systems, we calculated full QM Hessians, dipole gradients, and polarizability gradients, as well as partial QM/MM Hessians, dipole gradients, and polarizability gradients. Partial QM Hessians, dipole gradients, and polarizability gradients were extracted from the full QM quantities.