Yes, you are correct that the literal translation of "да ладно" is closer to "ok then" or "sure". However, its actual meaning is closer to "are you kidding" or "no way" in English. It can convey a sense of disbelief or surprise, and is often used in a casual or ironic way. It's important to remember that phrases don't always have direct translations between languages, and the meaning of "да ладно" is better understood through its common usage in Russian conversations.