Do you remember last time you waited for food at the restaurant? Didn't you think it took forever even though it wasn't that long objectively?
The same happens to all customers, if you want to secure a deal, you have to be even earlier than planned. You don't want to let these people hungry for your product for too long.
Are you a bit late in delivering what you promised you'd do? Bring on the starters while the main meal's still cooking!