Hi
Yes your intuition is correct - it is deliberate and common to ask several probing questions around your prepared stories, usually for 2 simple reasons:
- They want to test whether your story is in fact genuine (and not 'creatively constructed')
- They want to 'get under the hood' to understand the context / situation in more detail, exactly what you did, what obstacles you might have had to overcome, and the outcomes you were able to achieve
It's important to remain poised and structured in your responses, whilst ensuring the conversation remains organic and not too mechanical / pre-prepared.
Good luck for the remainder of the process!