Question for fight pass card timing?

Alright, the UFC website is all over the place on timing, best I can tell is the main card starts at 9 pm CENTRAL?! If I try to come in around the Birchak fight, which is the 6th fight on the pre lims, around what time will this likely be?  I have done a fight pass card before, cant remember how the pacing was, I want to say it was better than the FS1 stuff, but I cant remember. Im basically asking if the previous fights do not go the distance, do they add filler, or just start heading to the next fight ASAP.