so I understand that BargainFinderMax_BFRQ is used to search for and compare the lowest available priced itineraries across multiple brands for a specific airline and date. But what I am looking for is the branded fares (upsell) for a single fare in a different request. Meaning that when I find the right itinerary I want to be able to see if there is branded fares for this specific itinerary without having to do the search for all itineraries and compare it
Perhaps you could use revalidate itinerary, and then use the selected itinerary to make a second request with the Multiple Branded Fare parameter to get all alternatives to that exact itinerary.
The service will retrieve the upselling options including flexible fares if they are also available.
I hope you found this information useful.