[RightWhale]

announced a supernova that exploded 10 billion years ago and that was estimated to be 18 billion light years away.

Is it 18 giga-lightyears away now, or was it 18 giga-lightyears away when it exploded?

[apochromat]

It would make more sense to me if it was an estimate of the current distance. An estimate of the distance seen, instead, would be more directly based on the red-shift. I think they should give both distances, to make it clear.