[2022] Does 'Preparation' from the Mage Passive Tree include Channeled Spells?

Edit: I'm really unsure. From some testing it seems to be consistent, but it only increases by between 50-75% damage. So it may be reduced for channeled spells. Really wish the tooltip was clear on this.

Couldn't find anything online that confirms this. From what I've observed, it may be that the first damage tick works (giving +200% damage) on a channeled spell and then stops working afterward for the rest of the damage. Can anyone confirm this? If that's the case I can't use it for my build.