Replying to AR7 mounting question

I have the 2011 AR& and it has a mark on it that says -5 recommended mounting point. I was under the impression that recommended was -2.5? I don't think anything changed from the 2011 to the 2013 (or even 14?) so why do the 2011's say recommended is -5?

Also anyone know the recommended mounting point for the Libtech NAS freerides? mine has a plate on the top sheet with markings ranging from "sweet spot" to "core center" but I can tell it's not right.