Only 2 reasons why any TC will 'move in the bed and neither have anything to do with the brand of tie down.
First is the tie downs aren't tight enough and second is..
The tie down angle is too vertical. The front tie down angle must exert an angled pull on the front anchor points, the more angled, the better. The rears can be closer to vertical but also should be angled as well.
Side to side movement has to to with how slippery the bed surface is in relationship to the camper base and can be eliminated with side blocking or more applied pressure on the tie downs, either works.
I don't mean squat what system you use if the tie down angle is too vertical, the TC will move back. Even stake pocket Brophy's work so long as the attachment angle is an inverted 'V'.
I've run 2 campers now in a Line-X coated bed with entirely different bottoms and neither have moved on road or off road.
I have a pretty well rounded background in proper load securement. I hauled heavy machinery and steel over the road for 35 years. I know that 'splaying' the securement does and how it impacts load movement. A TC is no different than a piece of machinery except that with a TC, you actually have designated tie down points. With machinery or steel, you have to 'know' where to secure it to keep it from moving on a trailer.
That is how it works.