Generally, the system does not "track" mileage on the first fillup, because you need two points for an average. Also, if any of your fillups were marked as partial fills, they don't have MPG calculations either. If you mark a fill as a partial, no calculation is done for that, or the following fill. This data is used in your overall mileage though. Overall, you need at least 3 trackable points for the system to publish your vehicle in the searchable database because the numbers aren't reliable until you get at least 3 solid data points.