Is Liingo's Newborn Support System always required?

Both the Support Cushion and Headrest MUST be used with children under 11 lb or whose shoulders are below the lowest shoulder harness slots.

For children weighing more than 11 lb, the Support Cushion can continue to be used until the child’s shoulders reach the top shoulder harness slot, which at that point it MUST to be removed. The Headrest may be used until the child outgrows the seat.