My take on this, is first example is correct, HMS Zealous takes 14 damage counters.

For the HMS Victory, what is important is the initial fire value, its irrelevant what the ammo is, for now, so Victory fires with 7 plus 1 for every 3 point or parts there of, giving three more damage counters for a total of 10, then chevk tupe of ammo , double shot give 10 A and 10 B

Example 3 HMS Zealous fires with fire factor of 4 plus 2 extras for first broadside giving 6 damage, then see the ammo , as double shot, its 6 A and 6 B

Example 4 agree Heroe fires with fire value of 4 plus 2 for first fire , total 6 damage counters.