Oracle Financials - REST Batch Actions - What operation to use so that API honor the UPSERT mode

Summary:

When I try to use individual FSCM REST API say for Data Access Set assignment a second time, UPSERT mode in Headers works fine.

However, when the same is used via BATCH MODE API, the UPSERT mode is not honored and I keep getting "A record with this combination of values already exists."

Content (please ensure you mask any confidential information):

I have to assign/revoke a number of DAS (Data Access Sets) based on role assignment (happens via Azure Provisioning).

I can either run a loop over the standard FSCM API or use the fantastic BATCH Actions way.