[1.2.322] Moar Skill Balancing

I've always been wondering about Amp in terms of the new spell attack > spell % conversion. We know that % bonuses on other classes are stacked, not multiplied. So... does that mean Amp only adds 50% damage instead of the previous notion of x1.5?

I think it will still be multiplied, since it isn't +50%, it's 150%. Level 1 would add over 100% to all spells. Doesn't make much sense to me.