Looking at the schedule, FX usually does a movie from 8-10, followed by Archer and Legit. Pretty sure Archer draws and maybe they can get a few viewers off of that.
I'm not sure if TNT wants wrestling (it's supposed to be pure drama, pro wrestling isn't really considered that in the public eye) but they just show re-runs then too. From a business standpoint I'm not sure why you wouldn't want a show that draws a steady million viewers instead of just showing random reruns, but then again Impact is more expensive, but it also comes with built-in advertising with Direct Auto and whatnot