To avoid late delivery points you MUST have a lodgement scan event that occurs within your stated handling time.

Without this you run the risk of late delivery defects. If the delivery scan event shows it delivered inside their estimated delivery dates then you are also protected from the defect, but the lodgement scan event is the one to have since after that it doesn't really matter when it's delivered. Not your problem unless it is never delivered.

If you are using Aust Post as your carrier then ebay can automatically "see" into their tracking system and your buyer will not even see the question about the delivery date.

With other carriers (at this stage) your buyer will still be able to answer NO but if they do so, then if you can show ebay the lodgement scan event as per above the defect will be removed.