AC20 =((0.58*0)+(0.25*20)+(0.14*40)+(0.02*60) *0.15) = average of 1.77 extra dmg or 8% more damage
You can extrapolate for all AC's, PPC, and gauss, and even missiles.
For lasers
Assuming this graph is correct (here) you have 10 ticks per shot. That makes the numbers fairly easy
Large Laser does 9 dmg, and 10 ticks for 0.9 dmg/tick
Large laser =(((0.58*0)+(0.25*0.9)+(0.14*1.8)+(0.02*2.7)) *0.15) = 0.07965 per hit
If you hit with all 10 ticks on an open panel, you could expect to do 0.7965 extra dmg or 8% more dmg.
For mg's, lbx and flamers the iHP has a multiplier (different for each weapon)
Per this site (here)
flamers do 0.44 per crit
lbx does 2 per crit
machine guns do 1.25 per crit
mg = =(((0.58*0)+(0.39*1.25)+(0.22*2.5)+(0.05*3.75)) *0.15)= 0.18375 extra damage per shot into an open panel. You gain roughly 283% more dmg to internals
lbx = (((0.58*0)+(0.39*2)+(0.22*4)+(0.05*6)) *0.15)= 0.294 extra damage per pellet that hits an open panel. you gain 29% more in damage to internals. .
flamer = =(((0.58*0)+(0.39*0.44)+(0.22*0.88)+(0.05*1.32)) *0.15) = 0.06468 extra damage per shot to open panels. You gain 9.2% more dmg to internals
As you can see, the mg and lbx both gain significant damage from the change. The flamer and most non crit seeking weapons are in the 8-9% range.
EDIT : Updated numbers for mg.
Edited by Sprouticus, 08 August 2013 - 04:32 AM.