First a warning: Modifying the scripts can lead to serious problems if you call support and do not let them know this. In one instance, a user modified the scripts for the agents. As a result there was an agreement between his employer and VERITAS that for them to have support, he could not administer systems with VERITAS products.
Second, if you want manual failover, turn off AutoFailover as mentioned before.
I don't understand "there are no agents on this server". If VCS ihas resources defined then agents are running. If the service group can failover from one server to another, then the agents are running on both and on the server where it is offline, then it runs the monitor at the OfflineMonitorInterval (300 seconds) to make sure of the status.
To make service groups start on different systems, set the node name in AutoStartList to the node name you want the SG to start on.
So I suppose the App owner is there 24 hours per day in case of failure so they can order it to be started on the other node.
At least that is the way it looks to me after teaching VCS for over 7 years.