This ends up being precisely the same matrix element as that used in collinear SF-TDDFT, which gives us an idea about the good performance of the method. In conjunction with Kohn-Sham orbitals determined via ground-state DFT, the extra determinants that are introduced to make the excitation manifold spincomplete do incur some double-counting of electron correlation effects, although one may argue this is likely to be small because the number of additional determinants is rather limited. In fact, the same issue arises in DFT/MRCI, where the overcounting is potentially more severe, and in that approach an empirical damping factor is introduced for the off-diagonal matrix elements in order to limit the scope of the double counting.