Some people are having fuel weight problems, because FSX is giving them full tanks when they load the aircraft for the first time. Meah culpa, forgot to include the fuel checker to avoid that problem. It will be solved in the upgrade. To solve the issue, you have to use the load-out manager. Click on the external fuel tank boxes until the "x" appear and then click again on them to make it disappear. That will clear the fuel in the external tanks.