Miguel Zapico and his colleagues are working on a detailed ACKS project. To support their efforts, I shared one of the spreadsheets I used to develop the Revenue by Realm Type tables and other material.
Miguel noticed that in my spreadsheets that I'd used to build the tables (and the Auran Empire), I had the upkeep cost of urban settlements at 1gp per month, whereas in the book they are 1.5gp per month. The 1.5gp costs has resulted in some anomalies that others have pointed out before, but I missed it.
In any event, the correct value is 1gp per month (that's the value that underlies all the tables in the books). This will be corrected in the ACKS reprint.
Big thank you to Miguel for noticing the mistake.