First, we carried out a series of calculations to assess the qualitative and quantitative differences between various flavors of multistate CASPT2 in terms of the smoothness of the PES, the accuracy of excitation energies and the robustness against the number of states included in the model space. Second, we applied the developed methodologies to dioxetanone and appraised the paradigm of correcting lower-level results with single point energy calculations, e.g. CASPT2 energies on CASSCF structures. Moreover, the same molecular system was used to assess the ability of RASPT2 to be a substitute for prohibitively large complete active spaces.