As discussed above, we have explored the effect of spin projection on the quality of calculated J-coupling values and spin crossover gaps for two commonly used test sets. A particular interest in this work is the dependence of such calculations on the geometries one employs in such calculations. Specifically, we have used our in-house analytic AP first-and second-derivative codes to examine the extent to which spin contamination degrades the quality of the potential energy surface, predicted minimum energy structures, and ultimately the calculated (vertical) gaps between spin-states. We begin by reporting the results from our tests on a well characterized set of J-coupling parameters corresponding to a collection of nine transition metal complexes. Next, we examine this effect on spin crossover gaps for a set of 65 complexes compiled and reported by Hughes and Friesner.