We present a view on inelastic scanning tunneling spectroscopy of magnetic impurities relying on states of the total angular momentum J = L+S in the presence of a crystal field. We show that the selection rules for spin-flip scattering within the J-multiplet agree with the simple selection rules for the effective spin model, but also show the deviations from the latter for the transition probabilities. A reinterpretation of some recent experimental findings in a description based on the total angular momentum J is done.