Exactly. Probably 90% of the burden on a successful agile project is in setting expectations with stakeholders for an iterative delivery without a fixed scope. It can be a tough sell but it shouldn't be. If you've ever done a top line estimate on a fixed scope project, you know it's just absolutely not possible. Why set a deadline you know with 100% certainty you're not going to hit? Just bake it into the contract and upfront expectations.