NJO Maps

Hey, sorry if this has been asked before. I did a quick search and couldn't find anything about it.

I just started reading the NJO a month or so ago, and am halfway through Balance Point right now. I was wondering about the maps in the front of the book. It seems that the maps from Vector Prime to Jedi Eclipse are the same, despite the YV rampage through the galaxy. Only in Balance Point do they start tracing over their path to the core.

Now my question is, is there any reason they did it that way? I'm sure its probably nothing important, but I was just wondering.

 

Once the Vong started moving through the galaxy, the maps started having the invasion path traced in, and the maps have also been modified to show new planets. It's just to add a little variety.

 

Showing you what happened over the course of a year. Though I believe they started showing map changes in paperbacks after BP as well as in the hardcovers.

 

I knew they were doing it to show change, I was just wondering why it took them so long to update the maps. The Vong were almost to the core by the time they acknowledged it in the maps.
Thanks everyone.