When you store metrics with org.opennms.rrd.storeByForeignSource=true, the metrics are persisted with the foreignSource/foreignId instead of the internal database unique id.

When you persist flow data and you reimport nodes from a requisition this setting is ignored and the flow data is always associated with the internal node id which the user can't control. The concept to store flow data with storeByForeignSource would give users control for the flow document inventory mapping in the database.