It doesn't surprise me that they waited to turn in the waiver. If Chad's case had somehow miraculously been dismissed earlier this week, there'd have been a chance hers could have been, too, but now that they know he's going to trial, there's no way they'd not find probable cause for her, so what'd be the point of her sitting through the preliminary?
This was also probably why Means seemed so unaffected by the discussion about livestreaming -- he knew there was a good chance that Lori's preliminary wouldn't even happen.