This situation with saving ( larger amounts ) for TATL flights with an US connection by booking two seperate tickets are very common. Very often when DL/KL/AF pricing an TATL trip at 1k+ ( for example TXL-CDG-ATL-SAN ) the TATL part TXL-CDG-ATL can be booked on expedia/kayak whereever for something like $ 676 + the US connention as a seperate ticket for $ 283 ( all prices are made up by me ) saving you a couple hundred $ that way. I did this in the past and i'm certainly not the only one. And yes, i was always able to check the bags through.