Based on PES-2023 a dynamics analysis was carried out using QCT calculations at a temperature of 298 K for a direct comparison with experiments, focussing attention on the well-studied HCN(v1,v2,v3) product. It was found that the largest fraction of energy available was deposited as HCN vibrational energy, ~ 65%, and that the HCN product vibrational population was inverted in the CH stretching mode and not inverted in the CN stretching and bending modes. PES-2023 reasonably reproduces these experimental findings, which represents a second test of confidence of the tools used, PES-2023, QCT and the NMA method. We suggest that coupling and transfer of energy between modes immediately after HCN formation, associated with the classical nature of the QCT results, could explain the lower bending vibrational populations as compared to the experimental findings.