Field help (SQDDDAYLTI) 

Lead-time in number of days required to deliver the goods to the ship-to customer. The lead-time is initialized by the lead-time entered in the quote header if the address on the line corresponds the address in the header. If it is not the same delivery address, the lead-time is initialized by the lead-time of the entered delivery address. This lead-time will then be used to calculate the shipment date and the planned delivery date during the conversion of the quote into an order.
It the quote is about a prospect, the delivery lead-time is systematically recovered from the header.
The quote lines applying to non-deliverable products are not impacted by this information.