How does tech 2 works now?

If the damage you are about to deal is lower than a certain amount, you will deal more damage, provided by Tech 2. It will ALWAYS activate for Frenzied Attack and Thunder Blast. I've seen it activate on other moves as well and I think that what the above poster said is right. When someone uses, let's say Full Stomach, their defences will be higher and your next attack, because it'll deal less damage to the monster with the increased defence, Tech 2 will activate for this skill.