A few things stand out to me that indicate Amanda was not being truthful. (I think I'm in the minority here about my doubts of sufficient evidence to show acting in concert.) But I do think there is plenty of proof of her lying. And the lying is, IMO, clear indication of her knowledge of the crime at a point earlier than she admits.
1. When she said testified that Little Grant asked, what was that noise? She told him the chair turned over. IMO, that was probably true. But, it wasn't Laura tripping as she claimed, but Grant attacking Laura.
2. Whe Amanda testifed about the night after Grant admitted that Laura was dead in Texas. She said when I awoke the next morning......WHAT. How would anyone sleep a wink if they had just gotten that information earlier that day? Wouldn't you be too scared to sleep? You would lay wide awake all night, debating how you can escape? Right?
3. Her testimony regarding why the vehicle would be so full. Did she even know at that time that the boys would be going with them?
4. Her tears seemed real for things like her loss of money and jewelry and fear of the animals in the swamp. She even seemed really upset about Grant threatening to throw the baby out of the car window, but she didn't seem to have any kind of emotion for the death of Laura. That seems very odd to me. Wouldn't you be very upset that the boys mother is dead and dismembered? I never got that from her.