Comment on ``Nonextensive hamiltonian systems follow Boltzmann's principle not Tsallis statistics-phase transition, second law of thermodynamics'' by Gross

Recently, Gross claims that Boltzmann entropy $S=k\ln W$ is valid for any system at equilibrium, so that Tsallis entropy is useless in this case. I comment on some arguments forwarded to reach this conclusion and argue that the additive energy formalism of nonextensive statistics is not appropriate for the fundamental study of the theory for nonadditive systems.