It is funny that you should say that Neil, because I have always played the double shot on first fire only because I never find ships have time to reload doubled in the thick of battle.
If reducing a ships stern to a hulk at the end of a battle with nothing else going on I may relax this a little.
Leander, for instance had so much time to wander around the fleet before coming up with the Santa Ana that I allowed her the liberty of using double shot again. My general consensus, however would be that if one ship is doubling, then any other ship on whichever side, AI or not, if it has time to load should be allowed the same privilege.
Rob.