Group IV PAO has the lowest solvency of any oil group and also the harshest on seals. This is why you won't find a straight PAO oil. It will have some amount of group III, ester, or napthalene to give it some solvency and help condition seals. The group III and IV synthetic oils actually have less cleaning ability than conventional group I and II oils because of that lower solvency. Solvency is what breaks down sludge so it can be picked up in suspension and filtered out. The additive package has little to do with this. A common misconception is that detergents clean the engine, but that's false. Detergents keep the oil clean as a way of sludge prevention, but they do not remove sludge that's already there.
If you want to clean up sludge from your engine, the best way to go is an oil with a lot of ester. This is the basis for Valvoline Premium Blue Restore (VPBR) as it's ~60% ester.
The Mobil 1 EP claims to help the engine seals on the website. So it is false since the Mobil 1 EP 0W-20 has high PAO content, it will hurt the engine seals?