Ok, going through the 300 or so system we have data for appears to add about 76 new systems with A class HPGs, for a total of 124. The map still has enough gaps that a large portion of the inner sphere simply doesn't get news except by whoever is kind enough to bring them computer updates.
It just really appears the HPG network simply isn't very effective. I wonder if jumpships help with that, say they have a core computer that has all the "news", whenever they jump into a new system the computer automatically updates with the planet based computers, and vice versa. This could have massive hack potential, but would be one way to help keep everybody in the sphere abreast of the latest news.
Or perhaps there are enough systems we just don't have information for, the original 48 systems were when the HPG system was only in the Hegemony really, and ComStar has since built lots of new systems.
Still, it seems silly that ComStar hasn't built 2xA stations on every planet, as that would enable an interstellar near-real time communications system.