I don't think that's right,
LAMas. A couple of analogies first.
If you aim the left edge of the CB at the right edge of the OB for a maximum-degree cut shot, does it matter how far apart the two balls are? No, because you're focusing on a straight line (or a vertical plane) through two points -- the edge of the CB at its starting position and the edge of the OB.
If you aim the point half-way between the CB center and the CB left edge at the OB right edge (or, equivalently, the left edge of the CB at the point on the OB half way between the OB center and the OB right edge), we have what we call a quarter-ball aim. Does the resulting cut angle vary according to how far apart the two balls are? No, we know it produces about a 49-degree cut (ignoring CIT). Again, you're focusing on a straight line (or a vertical plane) through two points. Distance doesn't matter.
OK, now back to aiming with the ferrule. With the cue stick centered on the CB and aiming the left edge of the ferrule at the right edge of the OB, you can think of it as aiming a point on the CB that is half a ferrule (about 1/4") off center at a point on the OB (the edge). Again, it is two points determining a straight line (or a vertical plane), and it doesn't matter how far apart those two points are. Sure, the ferrule at close distance and an OB at long distance may even appear to be the same width, but that's of no concern if you are looking at the line or plane along the ferrule's edge pointing at the OB's edge.
Now with any of the situations I mentioned here, you do have the problem of aiming with something that is not in the center of the CB. So the dilemma is where to place your vision center to best achieve the objective of stroking the CB on the proper line. Should your vision center be over the center of your stick, with the aiming point off to the side? Or should your vision center be directly over the aiming line/plane. That seems to be a matter of personal preference. You may want to read what Dr. Dave's website says about sighting:
http://billiards.colostate.edu/threads/eyes.html#sighting