I'm happy when my mods are mentioned.I use Banish Settler Button.
Does it do so instantly? If it uses Disable & MarkForDelete, I think it takes some in game time for MarkForDelete to kick in. Settler would remain counted until this time.
After you click the button to banish it takes about 2-3 seconds for it to vanish.
Banish Settler Button works in two steps
1. Call vanilla function: WorkshopParent.RemoveActorFromWorkshopPUBLIC(Settler)
This function unassign Settler from any job and completely remove Settler from the workshop. It takes about 2-3 seconds. This function is called if the settler died.
2. Settler.Delete
This will help you Move Settlement Spawn PointYou can also use it combined with Settlers Calling and do something like if you want say a female doctor or bartender then you recruit a settler, not female, banish, try again.