Can you make a patch?
I was about to do one quickly, but then realized that one needs to consider how those values are supposed to cancel each other (e.g. when should (585) + (-585) be turned to (584) + (-584))
Retargeting to 3.1. Don't want to change 3.0 rules balance for final releases from the series.
In all instances of "Trade_Revenue_Bonus", replace 585 on 584, 1585 on 1584, 1000 on 999 and -1000 on -1001. That should allow to get the values expected more often since we round the results of applying this effects up, and 20.001 - 1 < 1 / 1442 that likely won't ever reduce expected revenue bonus at 1.