  We introduce a simple improvement on the method to calculate equilibrium
entropy differences between classical energy levels proposed by Davis (S.
Davis, Phys. Rev. E, 050101, 2011). We demonstrate that the modification is
superior to the original whenever the energy levels are sufficiently closely
spaced or whenever the microcanonical averaging needed in the method is carried
out by importance sampling Monte Carlo. We also point out the necessary
adjustments if Davis's method (improved or not) is to be used with molecular
dynamics simulations.
