So for instance, if you want to design a grav-focused laser that can hit unarmored starships, that's a DV 20 laser, where, disregarding range for the moment:

DV = 2.5 x sqrt( input energy / 5 )

If DV = 20, then:

20/2.5 = sqrt( input energy / 5 )

8 = ...

64 = input energy / 5

320 = input energy, in Megajoules.

FFS says a ROF of 10 is typical for starship lasers, so input energy is

3,200 Mj distributed over 30 minutes,

or 100Mj per minute,

or 1.78Mj per second.

What am I missing? Is this correct?