Hello,
As far as I know and according to this article Active/Active APM deployments are not supported.
"BIG-IP systems can support multiple traffic groups, also referred to as an active-active deployment, but you must restrict APM traffic objects to a single traffic group. The system cannot have BIG-IP APM related traffic objects in multiple traffic groups. This means that you must deploy HA configurations for APM traffic groups in an active-standby-standby (N + M) topology."
There are many other posts about this in case that you want to look further.
Regarding A/A deployments, it's a best practice to do the sizing of the appliances as if there were active/passive in order to not overload the appliance in case of a failover.
Regards,