Also, just thought of another thing. Depending on where you live and the particular year at hand, the heating season may well run from September through May, or somewhere inside of those months. While fuel use during those tails might be vastly lower than mid winter that still means an 8-9 month heating season, and depending on those other factors I mentioned it would certainly be possible to burn an exceptional amount more than your 3 cords. This is especially true considering you say you only burn for 3 months.

Plus some people simply might not be well versed/skilled with their stoves even if they have an efficient EPA stove like yours and don't operate them at proper efficiency. So many factors, now that I think about it.