How do you increase of self-hosted parallel jobs on Azure DevOps Services using an associated VS Enterprise subscription

I have a Visual Studio Enterprise License.

My Azure DevOps Service does not reflect this when looking at the self-hosted pipeline configuration under Project Settings > Pipelines > Retention and parallel jobs.

According to the the (i) info button:

Visual Studio Enterprise subscribers get one self-hosted parallel job as a subscriber benefit.

Does anyone know how I can get my Enterprise Subscription to show through to Azure DevOps Services (formally VSTS)? It was pretty simple to do with TFS, but am drawing blanks on ADOS.

My user account for both my Enterprise account and ADOS are one and the same - I was rather hoping it would just show through - apparently that's not the case.

The best I found was this page - but it's only for TFS and explicitly warns that: