As I understand it, that once the original dormant CA-7 has taken over, to switch back requires that the former dormant CA-7 be shut down before starting a normally non-dormant CA-7. If this is correct, CA-7 must take an outage whenever the primary has been down.
For continuous availability, it would seem to make sense to be able to swap between CA-7, so long as there is one available. Something similar to the idea with Datacom shadow mufs. With Datacom, the first Datacom to become active is the primary, and the second becomes the shadow muf. If the primary goes down for any reason, the shadow takes over. If the original primary is restarted, it is now the shadow. There is no outage unless it is necessary for other reasons,
You should be able to set the CA7 start up TYPE=DORM (Dormant) as the default and achieve the same results. If you are not please let me know.