I'm seeing some confusion around standard and premium or premium deluxe versions of airports. While airports that are available in the premium or premium deluxe editions are also available in the standard edition, they are "enhanced" or "hand crafted" in the premium or premium deluxe editions, BUT those enhancements are encrypted (hence the *.fsarchive files). While it is possible to modify a standard edition airport via the usual means, it is not possible (at this time) to modify an enhanced airport for those that have the premium or premium deluxe edition.
From what I understand, if one has the premium or premium deluxe edition, when MSFS is loading an airport into the virtual file system, it loads the standard edition data, then loads the premium data over that, then loads the community addon data over all that. But, since the community addon does not know anything about the premium or premium deluxe data, lots of weird things can happen. Which is why one must uninstall the premium airport from content manager in order to use a community addon airport.
The upshot of this is that if one simply wants to fix up the parking spaces and/or taxiways at an airport that is enhanced and encrypted for the premium or premium deluxe editions, one would have to start with the standard edition airport, make the changes to the parking and/or taxiways and then add in everything that the premium or premium deluxe airport adds/changes without knowing exactly what those changes are. And then instruct the end user to uninstall the premium or premium deluxe airport.
Of course, I could be completely wrong about all this.
...jim