Thanks for the comment, though it is three years old. I like the way you categorise Fisher as joint gain, because the little that I read of his work is to refute the notion of positioning. (I used this in an interview, when they asked me what salary I wanted: I simply replied from $0 upward; this was met with a smile and acceptable to them and has, to date, kept the relationship open. If you position yourself too soon, then you could rule yourself out.)
I also appreciate the category of advantage seeking for Chester Karrass's book, who discusses the idea of concessions.
And, lastly, I appreciate that, as a teacher of this stuff, you have noted that there are only four titles worth a rating. I guess the two others are Dawson: Secrets of Power Negotiating and Shell: bargaining for Advantage.