nor sure I understand the question. it's for a economy return flight (direct).
funnily enough you can sometimes get a Lufthansa flight to Copenhagen for around 1000 and that connects through frankfurt.
that's because copenhagen is more competitive from SFO.
with carry-on that's a way to game the pricing but I heard they cancel the return if you don't check in in CPH.
I just checked and you can get a flight with a 2 hour layover for $500. I'm not sure why anyone would pay 3x the price unless their company is covering the cost.