Not sure about where those other parms are coming from but have you tried just changing the values in the .flt file directly?

Here is another hypothesis. When a user kicks FSX off the flight nominated as the "default" flight (no not the flight called Default) but the one you have asked FSX to load as the default (I'll use the term "Start up" flight henceforth. This loads your "Start up" flight. If you then ask FSX to load the flight that you want to use it loads this over your "Start up" flight. PMDG warns that it this can cause problems because of carry over data. So it may be that the flight you want to actually use is continuing to use the ATC CFG defaults of the start up flight even though your last flight loaded had the correct ATC parameters in its PLN file. This is only a theory.

I loaded the FSX default flight and saved it as Default 2 after changing the ATC window to how I wanted it. I then made Default 2 my "Start up" flight so that it always loads when FSX is started. This ensures that this underlying flight has the correct ATC window parameters in the flight loaded on FSX initialisation.

The one I have the window in the upper right is not my default...never has been.

Thanks a lot for the help with this guys.

 

@Gregg - Yes I have tried entering the values manually. It stores them, they are the correct values, but the last two coords are not used. If I only have one flight in my folder (set with the correct coords), load it, open ATC (which displays the size incorrectly) and then save it I can confirm that the new flight will have the adjusted last two coords to what I saw on screen. Where FSX pulls these from I don't know.

 

@John - I think something like this is probably going on, but I'm not quite sure what... With nothing in my FSX Flights folder but the 3 files needed for the one flight and this flight set as the default (Start Up) it still fails to load the second coords. It makes no difference even though this is my only flight; I can click 'FLY NOW' or 'Load Flight,' either way same result: The top left corner will be in the correct position but the scale will be incorrect.

 

Sometimes I seem to be able to load a flight in FS (after loading the 'Start Up') which will remember the width, but not the height. I haven't discovered the pattern for reproducing this yet though...

 

 

@Gregg - Yes I have tried entering the values manually. It stores them, they are the correct values, but the last two coords are not used. If I only have one flight in my folder (set with the correct coords), load it, open ATC (which displays the size incorrectly) and then save it I can confirm that the new flight will have the adjusted last two coords to what I saw on screen. Where FSX pulls these from I don't know.

 

This may be why it's the correct size for me in the upper right.  The window can't go further to the right.

@Gregg - Nope, I tried positioning it over to the right corner (both top and bottom) but it simply pushes it out to fit the size.

 

I'm fairly confident that there is a solution here which will allow us to save the ATC window position and scale anywhere we like, it's just understanding how the program works so as to avoid the issues I'm having right now. The fact that I was able to open a flight which did call the horizontal scale, plus John's successes gives me hope any way .