In the official documentation, the section Creating a log forwarder indicates that the service account is only required in multi log forwarder implementations if the log forwarder is not deployed in the openshift-logging namespace but the Service Account must be added when a multi CLF implementation is created in the openshift-logging namespace. If the SA is not added, the multi CLF implementation sends an issue.

My suggestion is correct the phrase:

The name of your service account. The service account is only required in multi log forwarder implementations if the log forwarder is not deployed in the openshift-logging namespace. 

It should be something like "The service account is required in multi log forwarder implementations"