It's difficult to evaluate without knowing what your initial answer was. So I don't know why the interviewer is pressing on this topic. I see a few possibilities:
- She doesn't think you achieved the desired result (i.e., it was not a good example, or there was poor communication)
- She is probing for your learning abilities / ability to process feedback (which is odd if it was a success)
My general recommendation here is that when you get a question you don't understand why it is being asked, you should ask them WHY they are asking the question.
For example: “I believe we achieved the intended result, so it is not clear to me why I would take a different approach in this specific instance. Can you clarify why do you think that would be necessary?”
This will give you clarity on what they are looking for, and therefore you answer afterwards should be able to focus on what really matters to the interviewer at that point.
(edited)