In general, adding files to the Main folder leads to the mod becoming incompatible with multiplayer, in addition to the change not technically being in your mod. While it will most definitely work, it's limited to your computer and would affect all mods that you activate that are based on the Main Campaign.

Replace Main in the file path with the folder name for your mod (usually the name followed by a lot of letters and numbers) and it will be in your mod proper. Though you might run into the issue I ran into at that point.