  Recently, it has been argued that in the supersymmetric extension of the
seesaw-extended Standard Model, heavy right-handed neutrinos and sneutrinos may
give corrections as large as a few GeV to the mass of the lightest neutral
CP-even Higgs boson, even if the soft supersymmetry-breaking parameters are of
order the electroweak scale. The presence of such large corrections would
render precise Higgs masses incalculable from measurable low-energy parameters.
We show that this is not the case: decoupling is preserved in the appropriate
sense and right-handed (s)neutrinos, if they exist, have negligible impact on
the physical Higgs masses.
