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.
While comets *may* be billions of years old, they only spend a few days or weeks in proximity to the Sun during each of their orbits.