I am trying to write out to a DWG from multiple inputs and need the output file name to be a combination of variables i.e.

Extract_@Value(lot_number)_@Value(survey_type)@Value(survey_number)_@Trim($(_extractCoordinateSystem),EPSG:)_@DateTimeFormat(@DateTimeNow(), %Y%m%d).dwg
The variable creates fine using a variable setter

But when I try to run the writer it fails. It appears it is trying to write the file multiple time and fails to overwrite


Any ideas on how I could set the variable file name better?