Your point is, if it had a bunch of error (but not too much!) in one particular direction, the lifetime would be even further extended. This is true, and is pro

Your point is, if it had a bunch of error (but not too much!) in one particular direction, the lifetime would be even further extended. This is true, and is probably worth a mention in the article as it is an interesting fact of the mission. My point is, the 10-year lifetime was designed with the worst-possible underboost (opposite) error scenario in mind, so it's not at all untruthful to say that the accuracy of Ariane extended the mission. Ariane performed remarkably well, and that fact should be recognized and praised in the media. It's not exactly wise to hope for "errors in your favor" - much better to be more-precise-than-expected, as it allows them to plan more daring maneuvers with less margin in the future :)