What's the "three tier" system? I'm completely unfamiliar with Deltla's product or policies... hardly ever fly them. I'm 99% sure I'm switching my loyalty over to CO in January... I've been NW silver the last 2 years, sitting on 800K miles. I can get direct flights to CO where I need to travel, vs taking connections on NW/DL, so it seems like a no-brainer to switch.... I've been posting my CO flights to my NW account the last 3 years, because I've been using a travel agent and CO only wants to give me 50% EQM for those flights.... I guess I have to start booking my own stuff on continental.com when I switch over.