Have you have bought it via Marketplace or an other external webshop?
When via Marketplace, I’m afraid we had no chance due the new priority logic in the content file. You can’t prioritize Marketplace sceneries, they all we be loaded in alphabetical order. You have no chance to re-order it, sorry.
When you have it bought via an external webshop, we can re-order it. Therefore its highly recommended to buy 3rd party sceneries externally and not directly from the MSFS via marketplace. You are more flexible then.
Again, this works ONLY!! with sceneries which are not from the marketplace because the marketplace sceneries will be loaded automatically in the alphabetical order. So this sceneries can´t be prioritized - that´s per design of the MSFS and has nothing todo with us. Sorry.
the reason in this case is, FSIA is not included in the MSFS stock scenery and we add this airport in the default data (only the runway). When you now add a 3rd party scenery for FSIA, you have two equal airports one from us, one from the 3rd party scenery and therefore you need the prioritization in the content-file.
Normally, you don´t need to add all sceneries but in this case, you need it … due the missing stock airport in the MSFS.
Add the line in your content.xml file, restart the sim and try it again. It could be, that you must re-start the sim again, that MSFS recognize the changes, but that depends on your system. It must work …