I tried to rationalize the blasphemy of being able to see the five distinct lasers from Maz’s planet (even though the five targets shown were all within the space between Earth and it’s moon) as the shot hitting a few key planets/bases where the remainder of the republic fleet was. Meaning that the Hosnian system and its moons(?) were blown up by only one of the beams as seen from Maz’s planet.
At least that sounds better in my head.