Recently I had a DL TATL RT in D1 and the International Airline Program saved me about 20%, which was very nice on an expensive ticket. I booked with PTS by phone (easy as the agent seemed to know just what to do)and it appeared immediately in My Trips on delta.dumb. I got the five times membership rewards points and full MQMs/MQDs/RDMs from DL posted right on time. The PTS agent told me that it was a private fare and definitely not a bulk or consolidator fare.

I tried again for another trip where I had already found a quite good fare and the AmEx fare would have been higher. I questioned this and was told that for DL, the program includes discounts for all of the D1 classes (Z I D C and J) but only A P and F for domestic FC connecting flights, so maybe this was the problem in my example. This seemed to be some sort of a sale from DL as it was about a thousand dollars lower than when I had checked the same flights a week or so earlier. At the time, it needed to be ticketed within about a week according to the fare rules (and a normal number of days in advance for the Z fare) and availability went down pretty quickly, including for the good connections. It wasn't so special as to be mileage run or premium fare deals FT subforum territory.