Most likely, a higher temperature mash will lead to a less fermentable wort. There are a bevy of factors that affect attenuation though. Beersmith estimates an attenuation based on averages for yeast. So if your strain attenuates at 65-70 % it may do 67.5. Then it takes into account the fermentability of the wort. (I believe). This is done from a composite indexing of your grain points, expected mash efficiency, mash temperatures and such. Try going into beersmith, and correcting your infusion temperatures to what they actually were. See if it changes it for you at all.