The loss of volume wouldn't have changed the OG at all. Gravity is a measure of density, and a uniformly mixed solution doesn't lose or gain denisty no matter how much you dump out...one drop is as dense as 1,000 gallons.
The mash temp MAY have had a small part, but it wouldn't as a general rule change the OG. You get a DIFFERENT kind of conversion at different mash temps (i.e., different sugar and enzyme chemistries/characteristics), but not particularly more or less conversion.
I would think more about your efficiency and all the factors that go into efficiency, like crush, good sparge/mashout or whatever technique, etc.
Did you do any pre-boil gravity readings or otherwise record your efficiency? The recipe assumes 70% efficiency, so if you hit higher than 70%, there's your extra gravity points.
Either way, that spread is not enough to drastically change the characteristics of the beer, so I'd jsut roll with it and enjoy the slightly higher body and ABV!