We think it'd be a bit arrogant of us to think we have the best way.
You and your organization have learned a lot over the years, and we see no reason to change it if it's working. (If it's not, we will suggest methodologies.)
What matters to us is your happiness and the success of the project; how we get there is a component, and only just a component.
We adapt to your way of doing things, or we can provide a way to approach the project that works for us. How we approach it is per your preference.