How accurate is the fuel gauge? Seems my fuel tank goes down pretty quick to half a tank on a trail ride, my son-in-laws RZR XP1000 gets much better MPG. Seems a 10 1/2 gallon fuel tank should last longer. Not even driving that fast 10-15 MPG on the trails. We get back from a trail ride and I am down to two bars, he is over half a tank.