Only 1 of the 5 has the "Exchanged Ticket Number:", I never noticed that before because I would only open the first couple, had to open them all to find the 1 reference. So, still have the same problem, how do I find out how the other 4 were applied?

My guess now is that someone at Delta skipped this step when redeeming them and the history is gone forever. When I get some time I will call the DM line and see what they say.