Decreases in the amount of power in the interferometer from decreases in mirror reflectivity due to the absorption and scattering of laser power cause a decrease in the performance of interferometric gravitational wave detectors. Using established simulation software, FINESSE, multiple simulations are run to evaluate the effect of changes in reflectivity on a Michelson interferometer with power recycling. The results suggest that significant noise is added when the reflectivities of the end mirrors are unequal compared to when the reflectivities are equal.