Right. We don't have a very large sample size currently, so it's a bit premature for definitive statements such as "earthly water not from comets". All we know

Right. We don't have a very large sample size currently, so it's a bit premature for definitive statements such as "earthly water not from comets". All we know is that this comet shows a different fraction of deuterium, compared to Earth, and some other comets we've checked are all different. So the jury is still out. We need more data, lots more.