738 fuel tanks always returns to full?!

Hi,All of a sudden I got a very strange problem with my 737-800 I never had before, whenever I load fuel for a flight the fuel tanks are immediately returned to 100% fuel load as soon as quit the change fuel dialog.I have tried using both FS's internal fuel loader via the a/c menu as well as Ross A Carlson's external fuel planner ver 1.3.1. Normally I always use Ross's fuel planner which I find great and it has worked 100% perfect for hundreds of flights so I really don't know what has happened.I have also tried loading up a different flight and loading a different a/c and the fuel problem is not present but as soon as I reload the 738 it's back showing 100% fuel in all three tanks no matter what I do.Anyone...?Edited to add I just realized this don't seem to be a PMDG isolated problem after all. First I tried loading PMDG's B1900C and checked the fuel load and it looked normal (not 100%) but now I tried loading the FS default Bell helicopter and have the same problem...whenever I change the fuel load it returns to 100%. This is really annoying so if anyone has a good idea how to fix this I would really appreciate it!And edited again...problem solved! For the explanation in case anyone else get this problem, below's the explanation.http://forums.avsim.net/dcboard.php?az=sho...08714&mode=full