In the article, it states:

For a named instance, we typically only require two commands, because there isn't a case where a client is just connecting to the name of the server. For instance, let's assume we have a named instance called Instance2 listening on port 4444 on that same server using that same service account. In that case we'd execute the following commands:

SETSPN -A MSSQLSvc/MyDBServer:4444 MyDomain\SQLServerService

SETSPN -A MSSQLSvc/MyDBServer.mydomain.com:4444 MyDomain\SQLServerService

Isn't this command incorrect? The command is the same as a default instance.

Shouldn't this be:

SETSPN -A MSSQLSvc/MyDBServer:MyInstance:4444 MyDomain\SQLServerService

SETSPN -A MSSQLSvc/MyDBServer.mydomain.com:MyInstance:4444 MyDomain\SQLServerService