I wish you well in the search for the steels identity.
Having analysed steels in my previous jobs, I can tell you that the analysis does not tell the whole story.
Most steel types have a wide variation of alloying contents and can all be in grade. This is due to the steel being within its physical specifications and the chemical content can vary widely.
From your description it sounds like you got some high quality free machining steel, which I think contains Lead.

Peter