Threading dbi action occurence id in department hcm extract

We are developing an HCM Extract that captures changes only for historical and future Department details. The root UE is PER_EXT_SEC_HISTORY_ORGANIZATION_UE. When we use the organization ID as the threading DBI, we encounter duplicate rows. However, when we use the Extract Historical Organization Action Occurrence ID, we get unique rows. Is Organization Action Occurrence ID the correct DBI to use, and will it always be unique? Has anyone used this threading DBI before?