Today we published a small Live Update that, amongst other things, add the ability to specify doors heights as Absolute or Relative units. Absolute means the height is measured from the Ground level, Relative means the height is measured from the airplane reference point, which is how the aircraft.cfg works.
We added this feature because it might be easier to work in Relative units when starting from an aircraft.cfg file, because you only need to convert from feets to meters, without taking into account the static_cg_height.
You can select which method you want to use, by setting the following parameter:
absoluteheights = 0 or 1
IMPORTANT
If you are using existing GSX.CFG files, depending on which data source you started when customizing the airplane, that setting might need to be changed. This means, if (after the today Live Update), you have problems with your existing GSX.CFG files, open it with the GSX editor, and change absoluteheights to 0 (if it's 1) or to 1 (if it's 0), then Save it back.