It is shown analytically that the critical exponents for the 3D Ising model from a renormalized Hamiltonian treatment, given by Girvin, of the thermal averages appearing in an approximate difference equation formulation, are exactly those of the spherical model ( gamma =2, alpha =-1). These are compared to the values computed by Girvin: gamma approximately=1.78, alpha approximately=0.11, which do not satisfy scaling. It is also noted that the behaviour w( lambda ) approximately=W(1)+O(1- lambda )^1/2 for lambda approximately=1^- is reproduced by the Chadi-Cohen method of computation of reciprocal lattice sums only if the criterion q_i²<<1- lambda is met, where q_i are the smallest special points brought in at the order of approximation considered.