Crystal did not say when she saw Ron hitting the children..it was a rather short interview unfortunately. However, they were discussing the alleged abuse by Ron towards Haleigh and Jr when GR asked her that question. She did not clairify what kind of hitting like you mention in your post, so it leaves the viewers the impression that Crystal saw him hitting the children in an abusive way. I hope I'm making sense.
You're making perfect sense. I just don't think Crystal's comments indicate that she is lying.