Asking about project xy is different though, it's more guided. I think it's much easier to answer than the really open ended ones that ask you to pick an incident from all 10-15 years of your work history: the field there is so wide that unless I've specifically considered the question in advance I'm likely to sit there going ummm for a bit.

In general I think the question format favours people with a good memory for anecdotes and story telling ability.