That sounds about right. I had a game where ten of my Chaos Knights (maybe two groups of ten with the second leaving combat later) charged a huge unit of them and spent the rest of the game being chipped away by them. I am not actually sure who tarpitted who. I do claim a moral victory that my initial charge was devastating enough that even Bravery 10 didn't save them from a single ghost fleeing in terror while being my Chaos Undivided knights held firm. My opponent was not a fan of the Terrifying Champions special ability.