  10 years from now medium baseline reactor experiments will attempt to
determine the neutrino mass hierarchy from the differences (RL+PV) between the
extrema of the Fourier transformed neutrino spectra. Recently Qian et al. have
claimed that this goal may be impeded by the strong dependence of the
difference parameter RL+PV on the reactor neutrino flux and on slight
variations of Delta M^2_32. We demonstrate that this effect results from a
spurious dependence of the difference parameter on the very high energy (8+
MeV) tail of the reactor neutrino spectrum. This dependence is spurious because
the high energy tail depends upon decays of exotic isotopes and is insensitive
to the mass hierarchy. An energy-dependent weight in the Fourier transform not
only eliminates this spurious dependence but in fact increases the chance of
correctly determining the hierarchy.
