In IFS I am being asked to make the availability check at customer order entry check the entire structure for availability, not just the top part being ordered. Is there a reason why this would be needed. I found documentation saying it specifically uses the top level only. I was under the assumption that demand considers the components already, so there's no need for the availability check to also do it. 

The Availability Check at Customer Order Entry and Customer Order Sourcing

The availability check at customer order entry is a planned delivery date estimation based upon an organization's material constraints. It is an order-promising calculation that verifies and/or suggests a delivery date by analyzing material. It considers the available material for single-level product structures.