Annals of Bad Editing, The Witness for the Dead edition

I greatly enjoyed The Witness for the Dead, which follows the story of a minor character from The Goblin Emperor after the events of that novel.  

All of it, that is, but page 45 of the Solaris paperback edition:

Maps ... covered the walls, and there were filing cabinets full of written directions on how to get from the Prince Zhaicava building to every major landmark in Amalo.  I had overheard an argument one day about changing the starting point to the Amal'theileian, as being "more suitable", but ... the master mapmaker ... said sharply, "All that would accomplish is that we'd have to add directions from here to the Amal'theileian to the start of every script."  And there the matter ended. 

Of course, it's the other way around.  They have directions starting from the Prince Zhaicava building.  If they changed the starting point to the Amal'theileian, then they would add directions from the Amal'theileian to the Prince Zhaicava building to the start of every script; otherwise, they would need to completely rewrite all the filing cabinets full of scripts.

It's possible that something else is intended here, but if so, it's not at all clear.