Exactly! So say you have below setup (just as an example)
master fw -> 10.10.10.1
backup fw -> 10.10.10.2
virtual IP -> 10.10.10.3 (which would be the IP listed there in field you pointed out).
What happens is if you navigate to that IP, it will always associate with whatever member is active at the time. Also, I always tell people to change that port to something other than 443 (say 4434 or 10443), so if you ever enable mobile access blade, there is no conflict, but it also wont conflict with anything VPN related.
I just gave example with internal IP addresses, but you probably got correct one there, though you can always set any other inerface to be configured as mgmt one to manage this portal through.
Hope that helps.