This product is not advertised to "clean engines". That's more of a job for an engine flush, or something else.
This oil is designed to remove piston deposits of hardened carbon in the ring pack area. When this happens, it is USUALLY due to stuck rings, particularly the lowest oil ring and scrapers. When rings get stuck, it USUALLY manifests itself as oil consumption between changes.
I have seen the Valvoline video of the piston rings having the carbon removed.
What I have NOT seen is any evidence that this oil will remove sludge from the valve cover area or anywhere else.
I'm not saying that some cleaning of sludge MIGHT occur, it's just that this oil isn't sold as an engine cleaner.