Good connections and customer ownership.
In most businesses that I have worked for, there is still a disconnect between sales and the rest of the team. The customer is not owned by anyone, the information that one team gains should be shared with the rest of the team to ensure that the best solution/service is being delivered.
We can create an experience that enables a customer to set expectations and have these fulfilled and perhaps exceeded, but playing one business team off against another is a poor customer experience that I have witnessed in many businesses. This can be seen when one team plays good cop and makes their other company cohorts the bad cops. A statement like “Yes, we were also expecting that the development team would have finished by now as well” is a terrible thing to say about a project running over time. It doesn’t fill your customer with the right expectations and they may not work with you again, as you’ve admitted that your company has no idea what to expect.