One has to be a rabid fanboy or delusional to pursue the same idea that the Dodonna quote has to lead to an average firepower in the league of e26 J per warship's volley or some such.
Not only a quotation from "Death Star" would help mitigating the interpretation, but it would be equally simple to point out that there's simply no evidence whatsoever that the firepower of a normal warship scales up to that degree of destruction in the whole 6 movies arc.
From the asteroids flash destroyed which we know are not as big as formerly claimed for years, and also are quite special, to all facts we have which can use to scale up, such as:
- the Millennium Falcon's hull being threatened by the "bazooka-like" tripod gun carried by snowtroopers (E-web in the EU) in the TESB novelization. You'd think that would be quite short for a ship that's supposed to be able to withstand one or two shots if her shields would fail to absorb all the energy of a bolt fired at her. For the reminder, Wong calculates a shielding capacity in the megatons from TESB, and this fits with the numerous AOTC:ICS figures for ships of the same size, either for shielding or power production, which has to be in the same ballpark. A concordance needed to match with the act of scaling up those figures until you reach star destroyer sizes and the much vaunted teratons.
It's pretty obvious that the tripod gun, in the best case scenario, wouldn't come with a firepower greater than 1 GJ. And boy, that's already a silly kind of firepower on the battlefield you know, especially for an infantry weapon which was going to be used at close range!
- those same shields+hull actually threatened by asteroids which are nowhere dense and fast enough to match megatons of kinetic energy.
- TIE fighters in TESB described as threatening to the MF during the chase, yet whatever they fire hardly threaten the rock the bolts hit.
- TIE fighters in ANH managing to actually cause internal damage to the Millennium Falcon, meaning that their guns have to have been set at a level similar to the tripod gun. If they had anything like multi->GJ guns or even kiloton guns, the MF would have been erased from space by mistake.
Then you add several other examples :
- patches of Invisible Hand's thick hull burning up in atmosphere despite utter lack of former visible damage in those same zones.
- the same ship actually breaking up in two after an off-axis internal explosion nowhere close to even a multi-kiloton, most of which would have been directed outside since it happened in rooms open to space, with force fields allowing projectiles to fly out.
That's rather odd for a ship that is said to have megaton-level point defense guns in the ROTS:ICS. There's quite a huge disconnect between what is needed to withstand the mere shock of a megaton PD gun impact on your hull and going down because some sort of multi-gigajoule (being generous in fact, considering the yields of a single canister) blast ripping the same ship apart.
- top notch Jedi fighters in AOTC still being threatened by bolts that turn 3~4 wide asteroids which seem to be mainly amalgamated chunks of rock*, into still large and slow drifting debris. Again, 1 GJ per bolt is damn generous.
* we know that because of their behaviour when they collide each other, or when the seismic slicing plane goes through them (the slice manages to crack the smallest with very little heating at all).
- snowspeeders' guns (which are quite huge) don't cause much damage to merely frozen surfaces.
- and finally, the clear proof that the superlaser is a chain reaction of some sort that may result in an impressive event, but which is not the result of a direct energy transfer by means of energized particles from the battle station's main weapon, the situation is pretty clear. The former impact, which could be the only part eventually defined as DET, only blasts a limited arc of the planet and already is accompanied by a ring of whateverium (and all of this, from clouds of debris to rings, are seen to immediately slow down).
And I'm doing all of this without the EU. The EU is actually far more favourable to low ends than to the ICS claims. Same for the CWS.
So whatever Heliostorm is putting up is just gibberish.
Mind you, this is not surprising since coming from someone who, against the anti-DET camp, says the following:
"No, it's not at all. As has been stated repeatedly, just because an energy transfer has unusual effects doesn't mean that it's not an energy transfer. In case you aren't aware, DET is an incredibly vague term."
DET is, in fact, rather simple. Once the beam has hit, it's over. So if stuff still happens beyond that point, and in fact, if bigger stuff happens beyond that point, then obviously the DET theory is not the right answer.
What Heliostorm does is just repeating an extremely old counter-claim.
He shouldn't last that long, really.
Oh wait, the comedy writes itself!
He manages to equate:
"A small, one-man fighter should be able to penetrate the outer defense." <-
Genuine speech
with:
"Right, and a small, one-man fighter SHOULD be able to avoid the Superlaser. But it is also in no way a certainty."
:D
Like trying to swathe mosquitos with a cumbersome, extremely low ROF fixed artillery position.