Mobile Reports for Power BI Report Server

Hi Guys,

I cannot find any document that describes the licencing of Report Server. What i found was:

When you buy Power BI Premium, your subscription includes capacity in the cloud for the Power BI service as well as a license to run Power BI Report Server in your own on-premises capacity. If you buy Power BI Premium P1, for example, you get eight virtual cores (“v-Cores”) of capacity in the cloud, plus a license to run Power BI Report Server on up to eight processor cores on-premises.

Does anybody know how does it look for Premium P2, P3 etc ...? If I want to have Report Server in DR mode, do I need to evaluate P1 twice?

I do not consider SQL Server Enterprise for now.