It's a difference between "definition of success" and "the plan". They can't just say "we want to get off the pad and whatever happens afterwards, meh", they have to point it somewhere. So they plan out a whole flight to maximize useful data per additional success, but consider some subset of the plan to be an overall success.

I might go to the grocery store with a list of five things, but I only really need two things. Coming home with 3 things would be a success.