Well let me try.
First anything is possible next time around. It all depends on what and who is in charge of the interview. Prior to 2007 if someone failed the interview they were able to come back again, so that said, that pratice many be revamped by the next person in charge.
As for the last time, if one failed the cog they got to come back in six months. If one failed the interview, they were done for good. If one failed the psyche, they went to a panel for review. Many people made it past this part, but if you did not you were done. Now the medical due to the Hippa laws et al, was just a yes or no. The yes, or no was given to DAL, with no details, because frankly it is illegal do do son since about 1996.
I know many, like myself that were cut off in 2001. Hired, interviewed, or just invited that were given an offer to come interview again at our earliest convenience. I am sure that practice will continue.
I do not know if people that DAL has popped out of the process will get a second crack at it. Many of those that interviewed in the past are the most likely to do it again, and they believed in the process.