It would add up weight wise, and it’s one of the simpler parts. Jet engines are high performance precise machines with many quickly spinning parts. If you can’t bore a tube correctly how are you going to machine a high efficiency, balanced turbofan system?

That said it seems like did have a poor process where a part could be out of spec and they had no good way to check it. As they mentioned about Swiss cheese, you want as many layers as possible, and checks like that are needed.