They're both pretty up to interpretation, I'll admit, but the combination of the two together certainly seems to at least suggest that the production staff were going with the same assumption about the Alpha/Beta border being defined by Sol as Star Charts did.
Yes, the idea came from the show's staffers in the first place. The 1992
DS9 Techical Primer that was part of the information packet sent to prospective writers (like me) says: "The Federation is located on the boundary between Alpha and Beta Quadrants". The first-season
Voyager Technical Manual for writers, from 1994, has a map that's basically the template for the
Star Charts version -- a rough chart of the Milky Way Galaxy with Earth on the Alpha/Beta boundary, the Cardassian Union in Alpha, the Romulans and Klingons in Beta, and
Voyager's location way, way out on the rim of the Delta Quadrant. The credits to the VGR Technical Manual say "Illustrations by Doug Drexler," and Doug was one of the main artists on
Star Charts.
And the antecedent to the idea goes back to the early days of TNG, before the quadrant convention was even established.
Here's a galaxy map from
Starlog's 1992
TNG Technical Journal magazine special, which is a fancier, redrawn version of a map printed in the
TNG Writers' Technical Manual at least as early as 1989 (the edition I have). It doesn't have quadrants, but it has the line between Earth and the galactic center defining the 180-degree coordinate, and you can see how it's the original ancestor of the later
Star Charts model, with the same relative positioning of the UFP, Romulans, and Klingons (though all three occupy a far vaster volume of space than on modern maps, since this was before DS9 had ships routinely commuting between Earth and Bajor or Cardassia and Qo'noS in a matter of days).
By the way, that '89 TNG manual defined a quadrant as 1/4 of a sector, no doubt as a rationalization of those "only ship in the quadrant" lines from TOS. Clearly the writers of "The Price" did not feel bound by this.
