I have set it up on 1 workstation with the keys stored on the Sims server and the usual Examin/out folders mapped through the A2C software.

As has been mentioned I also have the program shortcut delivered to a group through program set so if the Exams officer is off sick then another member of staff can run the program.

I cannot see a reason for having it installed on more than one workstation as I feel that is the way it has been designed to run for security reasons but that is just my interpretation of software and it's instructions.