Yes, it sucks but on a cluster that is the case. It is for failover and usually cluster setups should have a new instance on a different cluster node.
The plus is you will not have to install a new instance, only the server and disk resource for a second SSAS install (Multidimension can be on default/named instance and Tabular on a new instance with no sql server service).
Thomas
Thomas LeBlanc, MVP Data Platform Consultant