Can we actually be sure without stacking to a theoretical 100% (if it's A+B) or stacking to at least 50% and running a hundred battles? Or does it show on the in-battle text (I usually have FF on so I'm not paying attention)?
Also, it MIGHT be 3rd turn Activation + is A+B while 1st turn is A*B due to the fact you're taking hits the first two rounds. IDK, some testing would be required.
As for the affection based, IDK if that works differently.