  This paper is a contribution to a program to see symmetry breaking in a
weakly interacting many Boson system on a three dimensional lattice at low
temperature. It is part of an analysis of the "small field" approximation to
the "parabolic flow" which exhibits the formation of a "Mexican hat" potential
well. Here we complete the analysis of a renormalization group step by
"evaluating" the fluctuation integral and renormalizing the chemical potential.
