Sir 82 Their reasoning is specious, of course, but at least they acknowledge the sources which discredit their attempts to use 607. That's more than they've ever done in print.
It might well be a form letter as Room 215 suggests. It would be interesting for someone else to submit another query and see if they get the same reply.
I'm absolutely amazed they sent you such a detailed letter. Many have submitted similar queries with zero response. I think, too they must have had so many inquiries they've decided to trott out a standard response from now on.
I say they're getting more worried about some of the big criticisms they are getting - 607, micro managing, beards the list goes on.