Yes for PvP, however now that I test it on my second Warlock, it seems gear dependent.
On my full Mastery/Haste Warlock, it’s closer to 3x, just below that original figure.
https://i.imgur.com/WjanlYp.jpeg
However, on my Versatility/Haste Warlock, the gap is smaller, it’s closer to 2x.
https://i.imgur.com/s5Iy1OF.jpeg
Using my Vers/Haste Warlock as the example as that’s the standard stat priority, a single seed on a PvP enemy currently does 40k damage. The new one will do a bonus 25k damage with that 25% UA. (Total 65k) UA currently does 100k so still better against a single target and both spells have the same cast time of 1.3sec in the seed build.
Against two targets, it gets more complicated.
Main target seed: 40k
Second target seed 50% weaker: 20k
Since it only applies UA to the main target, that’s a bonus 25k.
Brings us to 85k, however, seed also does AOE damage but not at the same damage as it does to the host which gets a 50% boost through talent Patient Zero.
So if both targets are within 15 yards, add another 26k to each, bringing the total to 137k.
Conclusion, single target in seed build it’s still better to use UA, however, as soon as there’s a second target, seed far and away takes priority.