That's correct. 'Extra' hits from a lethal zone don't count towards the 'everyone takes one hit each first' limit.
I understand artillery (2xD6, Artillery or Dropped, Lethal Zone/2"); nominate an impact point, scatter it, and then roll the damage die or dice against each model caught in the lethal zone.
I understand single-die direct fire weapons (D6, Lethal Zone/2"). Roll all weapons in the shoot action, place the LZ-causing die in the appropriate place, then roll an extra die against the guys caught in the lethal zone (whether they have any other dice assigned to them or not).
What I'm not clear on is multi-dice direct fire weapons (2xD6, Lethal Zone/2") - the one that springs to mind most clearly is the Hydra rocket pack in Modern Combat.
If I have a hydra pack and a machine gun, I follow the standard shooting rules - nominate a fire zone, and roll 2xD6 for the Hydras and 2xD6+1 for the M2
Imagine the results are 2 and 5 for the hydra and 3 and 6 for the M2.
I now have a spread of hits that goes M2, Hydra, M2, Hydra, as you go back through the unit.
If I follow the rules right, the hydra hits then generate a lethal zone of 4", and roll 2xD6 against anything caught in it.
My questions:
1) This seems to mean two potentially overlapping lethal zones (especially given their size) so some unlucky sod catches double damage - is this correct?
2) How much damage does the lethal zone effect roll - Imagine a string of three ones instead in the example above, so only one hydra hits and no other damage is done. If one rolls 2xD6 against each model in the lethal zone, then it's 2xD6 for anyone within 4" of the rocket's detonation point but bizzarely only D6 for the person hit in the face by the rocket itself.