I second (third?) the request for an option to post both "calculated by real-world tank" and "computed" MPG averages. Maybe after a few months of collecting such data, we can work out those discrepancies.

I'd also like to see, instead of a "which month" dropdown menu, something more like a "from the last tank date to 'now'", where you'd just fill out the 'now' date widget of course.