No, I didn't. I just scanned it.
A "potential impact trajectory" is far different than knowing that something will, for certain, dead center us and that we can apply a fraction of a ounce of tugboat force for the next 18 months to steer it off by a fraction of a degree.
Exactly how much certainty do you think they would attach to the projected trajectory of something some 872 years out. Space isn't empty. Calculating it to endless decimal points doesn't help when there are a whole host of unknown variables (gravity of other objects, particles and matter in space, em effects, etc.)