“At the same time”, or “Within a few thousand years of each other”?
Exactly. For example while the Chesapeake Meteor strike of 34 mya was 60 miles in diameter from Norfolk north, there was a 9 mile diameter crater left off Toms River in NJ, plus the 50 or 60 mile diameter crater in Russia called Popogai. All at roughly the same time, but perhaps not the same hour or day. All together they managed to change earth conditions enough to cause a 30% die off. On the other hand the recent Shoemaker-Levy bombardment of Jupiter was very quick.