I assume you're looking at Admin Console->Batch Process Control->Setup?
I'm afraid this particular view does not show the true state of things. There are a few such known issues we are aware of but I'm afraid I don't have an ETA for addressing them.
If you want to configure or view the current enabled workers, please look at /opt/kaltura/app/configurations/batch/batch.ini.
On each batch node, under the [HOSTNAME : mainTemplate] section, there are multiple enabledWorkers.* directives. The value for each indicates how many of each worker should be run simultaneously.
Further down the file, you will see specific directives per worker.