Hi Kenneth,
If you have Smart Redundancy with Management IP, then you can access the controllers with individual IP assigned to them or through the management IP.
However, if you are trying to access the Management IP, then whichever the ZD acting as "Active" will respond to it.
So, if you want to access only the Active ZD, then add the only management IP, if want to access both Active and standby in some cases, then add Management IP and individual IPs.