There is nothing wrong with the computer. It's just that when you ask a computer to price a fare originating from a foreign country to the USA, the fare calculates it as if it is originating from the USA as the higher fare applies. You have to command it to price FROM the origin country and that you have to be able to force the command in.
The only CRS that will not add the differential fare are the ones that are based in Canada! It's some strange law that forbids Canadian based computers to fare the higher fare.