Just got my xb a month ago brand new. I'm not sure if I'm getting the correct range and miles per tank. I last filled up 12 gallons and my full tank before have me about 286 miles. Is this normal? Also why does it say its 14 gallon tank?
It says it is a 14 gallon tank because it holds 14 gallons when completely empty (not empty on the fuel gauge, but like new in the factory before it is installed and has any fuel added or if you actually run out of gas).
You mileage will vary depending on your driving style/conditions. Brand new mileage tends to be a bit lower until the engine breaks in.
Your tank was almost 24 mpg (23.8), so if mostly around town, about right.