Question on AFCAD files

Some of the great products around for FSX are increasing flight realism to new levels. So to further the reality of the simulation I am thinking of making some changes to runway usage to match more of what I know real world operations to be.

I have tried previously downloading and installing various AFCAD files for some airports. Unfortunately I don’t do enough of this, nor do I get enough time in FSX period, and I may have forgotten which AFCAD files I have installed and to which airports. (I say “AFCAD files” as being files that change the runway assignments for landing and sometimes separately for take-off to better match real world configurations, or just to make the airport more flexible by assigning different runways for landings and take-offs, to ease “congestion”….). Am I correct that I need to uninstall any previously installed AFCAD files prior to installing new ones for any given airport? Or does the latest file just over-ride the previous one?

I also have the Flight 1 software AFX, which offers many features for modifying airports, including - I note - assigning runways for landing and take-offs, or both. Does this application also create an AFCAD file when I use it to change runway usage data? Or is it more like modifying the original scenery file without adding additional (AFCAD) files?

This topic might be better suited to the TTools forum, I'm not sure. I have asked similar questions before, I guess I'm just a little slow at understanding how this runway control works in FSX. :)

Thanks, Bruce.