I always think the range seems high. I have a tjet 150 and even on less than a qtr tank it tells me I have 150+ left which clearly isn't right. I've got the average mpg up to 55 before though, but that was jumping straight on the motoway after putting half a tank in and doing a 2.5 hour traffic free stretch down the motorway on cruise at 60mph. I know you usually knock off about 5 miles (I think) from whatever the readout says.