I would posit that, "On the same page," has become the "modern" (circa 1970 - current) version of this series of idioms simply because of the proliferation of "Talking Points."

The various phrases:

imply a "progression" based upon other idioms or common experiences currently in use in the vernacular of a particular demographic. All of which mean the same thing -- "We agree." It is possible that this meaning has in fact progressed from "general agreement" to "complete agreement," but "complete agreement" is its meaning today (2014).

"Talking Points" are encountered extensively via the media (Television, including Cable), and their use of "Talking Heads." These "Talking heads" rely upon "Talking Points" during their 3-7 minutes of airtime to convey the "pre-approved" point of view on the given subject.

"Talking points" are used to assure agreement and common response by spokespersons or surrogates to any "political" nor "sensitive" topic. They are used to sell your product, your point of view; no matter if that product is a new widget, a different brand of soap or a political policy position. They are, in fact (if done well) are a one-page list of items, thereby making it easy to be "on the same page."