Hmm.

Maybe it's the level of the persons 'self awareness' that determines how conscious a person seems to be to oneself. If someone doesn't fully recognize that they've performed a certain action until afterwards [as you described] then it seems to be a matter of self awareness and not consciousness playing the main part. If you didn't have consciousness then you'd be un-conscious or perhaps oblivious, non-aware, and so unable to perform the action in the first place[?]

It's an interesting question and in fact the question of consciousness and how it comes about is still a mystery to science. They haven't explained it.