BE2014 Dedup storage device keeps jobs queued, only 1 job runs at a time

Backup exec 2014 with dedup storage on a local disk. 

Concurrent operations has been set to 8.

BE Media server has been rebooted several times.

Yet when a number of jobs that kick off at the same time start, all with the dedup disk as the destination, only one runs, the others sit at queued, then the first job finishes and one of the jobs sitting at queued starts processing and so on. 

Its as if the concurrent operations value is being ignored and is set to 1 when it isn't.

These jobs have GRT enabled and are all using windows agent.

What could be missing?

With the jobs running in sequence instead of parallel is obviously stretching our backup window.

Thanks.