It is done when we have to use an annexure or if we want to differentiate a specific process for ease of reference and/or analytics.
In two scenario where sub audits are used:
1st scenario: When annexure is used. For every annexure, sub-audits need to be created.
2nd scenario: Sub audits can be created even without annexure for proper classification of checkpoints. We have a multi-level hierarchy under specific audit-type. We can add partitions in audit-type by adding sub-audits. Under sub-audits, there are groups which are sub-processes and individual checkpoints.
