I handled the note at the CNA, and one of the members at the table answered when I asked him the same question as eyevet, that he would grade both sides individually. That would be the case if a note was one grade on one side and another grade on the other.
For a note like this, I think because it is kind of a unique circumstance, the "dfescription" should be exactly what eyevet wrote in the post. And I would be that if this note was put onto the open market with that description, the final price would be reasonable close to what the midpoint of what the grades would be.
I must admit, I was puzzled at first when I saw the note on how to grade it. Working with Journey series, this case is not too common.
Huds