Thank you for your post, and I apologize for the late reply.
Are you specifying the printer in Print Setup and in the Print step? If not, then the script will print to the default printer at each workstartion. Make sure you are specifying the exact printer, and make sure each workstation is set up to print to that specific printer. If not, then FileMaker will not be able to find the printer and it will print to the default printer for that workstation.
It's been my experience that not all options specified in a print setup or print step are retained. In our case, a custom page size must be manually specified by the user each morning after opening the database.