Thanks, I did not know that.
I'm using USD. I noticed that the update balance was also doubling the value that I used.
So what is the proper process for using the currency? If I want to assess a 10% penalty on the current balance, how do I know what the scaling factor is? Do I care, or do I just operate on the internal values?
A GS doesn't need to worry about currency of clients. 10% are the same 10% - irrespective of what units you use to display it. The conversion of the money to a currency displayed is done by the display routines of OpenTTD, outside any scripts or NewGRFs.