In the next analysis, we investigated the errors that are introduced through the PHVA approximation by comparing full and partial QM Hessians. This comparison revealed that if the environment participates in a normal mode, the errors in frequencies due to the PHVA approximation generally increase. However, with respect to the errors in the intensities, the truncation of the dipole and polarizability gradients was mostly the dominating factor rather than the transformation to normal coordinates using an approximate transformation matrix.