Note: 31st-century communication suffers from few of the light-speed delays experienced by 21st-century long-distance callers. The conversation taking place between the Colonel Pranger and the Serial Peacemaker used hypernet relays, so that although light would take 38 seconds to travel from one ship to the other, they could talk in "real time." The 'circuitry' in the hypernet equipment used, which has a signal path of four micrometers (plus 48.3 cm, because there's this one really long, stray wire, but I digress) introduces more delay into the conversation than does the wormspace path taken by the transmitted message.
The launching of a missile, however, is not something you typically "announce" over the hypercomm. It's rude enough to fire it in the first place, and the odds are good that if you're launching missiles, you'd prefer your targets not find out about the incoming missiles until they can see them coming, or (in the best case (for YOU)) until it's too late to do anything but assume crash positions and fire a message off to their next-of-kin.