Did the manager add it? He said it was added, not but didn't mention who added it. I read it fast got the impression that no one was sure who added it?
Confusion came from here: "The Manager of Aerial Signs reported that he had told his pilots to not use Marvel Mystery Oil any more. In addition, he talked to the mechanics, and they had not added it and the pilot reported that he had not added it".
I'm sure it was added, and positive no one followed directions.