Originally Posted by
jetsfan92588
Interesting, I'm able to do it in Amadeus (using a UI), but the price appears to be identical to flying the entire itinerary in D1/F. I guess the only benefit of that would be if F was sold out?
Yes, if you see the same price that's just delegating the premium fare to a lower cabin which is generally legal but kind of pointless if premium inventory is available.
What I think OP is suggesting is taking a fare break in the gateway city and then using an Economy fare for the first fare since it's separate anyway. This usually requires separate tickets due to combinability rules on international fares, and even if not DL self-service channels require a break in travel of stopover duration at fare break points.
In general, it's not even cheaper to do this, but doing a fare break in specific competitive cities like JFK can indeed provide substantial savings (e.g. ATL-JFK / JFK-Europe with a fare break is likely to be cheaper than ATL-Europe).