As discussd above, without the constraints above, a CASSCF(2,2) calculation could easily produce two active orbitals localized to the bath, which would not help in describing the molecule-metal charge transfer problem. Thus, the constraints above are necessary. That being said, these constraints are not yet sufficient as far generating a balanced set of active orbitals; one still must perform a state-average CASSCF(2,2) to get meaningful excited states.