The tax works by ADDING additional percentage on top of the existing percentage set by town.
+0% = 1 to 999,999,999
+1% = 1,000,000,000 to 9,999,999,999
+2% = 10,000,000,000 to 99,999,999,999
+4% = 100,000,000,000 ++
eg: if you at Rome (2% default), selling item beyond 100b will cost you 6%!
This is WAY TOO MUCH.
Please either reduce it or let us change the item prices without re-listing.