  We consider a low-energy effective theory of the next-to-minimal
supersymmetric Standard Model by decoupling all scalar states except one Higgs
doublet and the complex gauge singlet. The mass spectrum of the resulting
singlet-extended Standard Model is calculated from two different perspectives:
1) using a matching of the scalar sectors at next-to-leading order; 2) using
the simplified-model approach of calculating the masses in the effective theory
at fixed order at the weak scale ignoring any connection to the full theory.
Significant deviations between the two methods are found not only in the scalar
sector, but also properties of the additional fermions can be very different.
Thus, only a small part of the parameter space of the simplified model can be
embedded in a well motivated SUSY framework.
