Need help with AC4 Black Flag mod

Can anyone tell me why the mod tool isn’t working? I’m not receiving any errors. I load my save into Horizon, max stats, save back to flash drive but it’s not changing stats. I have multiple backups of save file and none of them will take. I’m at a loss. I remember having a similar problem with AC 3 but it worked itself out after getting through the first few missions. I don’t imagine that’s the case here as I am 25% into the game. Any help will be greatly appreciated.