My all time max for distance on a tank is 236.8 miles. Of course, I've never seen 50MPG either though.
Your range on a tank is dependent on many factors, including how full you fill the tank (i.e. filling to the brim vs. filling to the splash plate), throttle usage, ECO vs non-ECO modes, terrain, and temperature. Range to E is a subset of that information.
As always YMMV.