I believe that is normal. Only one label job will run at a time.
TSM sequentially ejects tapes. I am running TSM on 2 AIX servers with a 3494. Each TSM server can issue simultaneous eject requests, but each server's requests are processed one at a time. For example, my Move DR Media job will wait if the I/O slot is full to issue it's next eject request. Once the I/O slot is emptied, the job will continue. It does not send all of the eject requests then exit, it waits for each one to complete before issuing the next eject request.
Andy