Up to five protection policies can be assigned to a single volume. A single protection policy can have up to 3 Tasks.
The idea of multiple Tasks is similar to setting up backup retention policies using a grandfather-father-son approach, each with different snapshotting frequencies and number recovery points that need to be retained.
Pivot3, Acuity [HCI]/10.6.1, Datacenter
Remote Replication Granularity, Disaster Recovery, Data Availability