Company X is most likely not the manufacturer, but a reseller. If so, their only option is to glue it, which is why they market "layers shifting". Natural latex is naturally abrasive (the layers grab each other) and does not shift. PlushBeds has done extensive testing on this, and you would need to hold your mattress up to a 90 degree angle before seeing any movement at all. Further, a huge disadvantage to glued layers is that if your mattress is too firm or too soft, your only option is to return the whole mattress (instead of simply switching out a layer).