I don't think any of this has to do with the original Plame name game. That's long done and gone. This is about who said what and when since then. I've never heard of a friendly perjury warning. Sounds fairly nice. Let's hope so.
Didn't Starr give Clinton a friendly heads up that he had "the goods"?
You are probably right about the shift in emphasis.
This prosecutor wants some meat for the cost of putting on the show, and if he comes out with nothing, there will be a lot of crap.
So I think it's perjury he will look for, even though it won't hold up at trial.