The term, "Next Business Day Onsite service" refers to the onsite technicians obligation to call you to schedule an appointment by the “Next Business Day” after receiving the part from Dell. We do our best to keep replacement products available for our customers and a large majority of orders are shipped within the time frame referenced at the point of contact. However, some products are provided to Dell by vendors. Due to many factors involved with the fulfillment of third party orders, a delay in any vendor component will result with a delay in the shipment of your order. Dell is unable to guarantee any delivery dates. Any shipping information provided on our website, by sales representatives or technical support agents is an estimate only and subject to change based upon availability. The name of the contract can be confusing, but we certainly cannot send an onsite technician out if he doesn't have the part in hand.