Hi Nagora,
I can help with this one, even though I'm not Gary. When Gary laid out the income and goods/service price lists in the Yggsburgh book, he did so using $ amounts that were supposed to be translated to gold piece equivalents. The editor made a few mistakes along the way, but we are presently addressing this in the Yggsburgh Town Expansion modules (Moat Gate and Town Halls District presently available). This includes revised price lists in the shops as well, should the GM wish to adopt Gary's suggested system in which the exchange rate is such: 1 gp = 50 sp = 500 cp.
Anyway, the mayor was presented by Gary as earning $300,000 per year, and each Council member earning $240,000. So, as you note, the editor did not exchange the $ amount for the gp amount.