this is true, but think of it like this... it's like Ulhuadshi when he steals your buffs, he hits significantly harder even though there has been no level change; now 20% isn't going to be as big of a swing as it is with Ulhuadshi, but it should still be big enough to see significant damage increase by your DDs. Imagine AV or PW getting hit with Impact (if they aren't immune, anyone ever try?)