Isotons are inconsistant. As for "The Ship" example, you're also underestimating them as well since the Jem'Hadar were not using them to directly attack the captured battlebug, just shake it up a bit and rattle the Starfleet boarders holding it. As it was, we know a direct hit would have destroyed the ship:Mr. Oragahn wrote:Doesn't work. There were something like 12 isotons concussion missiles fired at the surface of a planet to get Sisko and co walk out of a crashed enemy ship 468.48 GT would obviously not be in tune with what took place in the episode.
O'BRIEN: I've managed to bypass the virtual display interface and hook up a tricorder to the ship's sensor array. Those are ultritium concussion shells they're detonating.
DAX: Without shields, a direct hit would destroy us.
WORF: I do not believe they're trying to hit us. Their targeting systems cannot be that ineffective.
O'BRIEN: They're trying to rattle us.
We do know from the visuals that the shells were not being detonated very close close to the ship, or Sisko and Worf would have been hit with some pretty serious shock waves and debris when the negotiations with the Vorta broke down and the shelling started.
It also occurs to me that Picard's theory on the warhead reactants might still have something to it, since 12 isotons of ultritium will not necessarily yield the same explosive amounts as anti-deuterium would. Even still, why use the term if regular tons of explosive energy can still apply?
-Mike