Answer: Searching 'ID' will locate documents with that specific document ID number. Reference ID is a field we use to map to certain fields when the client needs to do certain things such as producing in chronological order. By default, reference ID is not mapped. So if the client is trying to call up a certain document, that is simply a plain ID search: 'id(###)'
Reference ID is not a useful field unless we map it to something during ingestion, such as a date field or some type of internal ID number. Make sense?