My thoughts are he used the whole grain bill, and the recipe calls for a 6.25 batch. If he mashed and sparge with proper levels for the 16 pounds when he was only making a 5G batch, that would explain part of the OG overage. But like you Noth said: how much did you collect, what was the preboil, how long did you boil, how much into fermenter. If these were answered earlier, I missed them