The ratio in comets and the oceans works out to about 1:6410, the ratio in Jupiter and other large extraterrestrial sources is about 1:6420; since the deuterium or heavy water is more prevalent in comets and in Earth’s oceans, stripping the neutrons would give the opposite result, similarly to differential heating.
I was commenting on what the article above postulates, that this particular comet differs in ratio.
My musings are the sun could possibly change these ratios over a few billion years' time, due to it's influence when comets pass by, thus making the ratios valuable for comparison, but not for absolute statements.