A known problem with QCT calculations is their classical nature and as a consequence the ZPE (zero-point energy) violation problem, i.e. some trajectories can end with vibrational energy below their ZPE. In the present study we have contemplated this issue considering only reactive trajectories with the vibrational energy of each product above their respective ZPEs (DZPE approach, double ZPE approach). Note that this approach is physically reasonable although it drastically reduces the number of reactive trajectories for the final analysis.