You're correct, there's no way to tell unless extensive experimentation is carried out. For that, OVERKILL would need to use the Premium Plus and Skippy would have to use the special blend that OVERKILL had made to see if they experience an improvement on Skippy's part and a slight reduction on OVERKILL's part.
There again, as I mentioned, the difference in their perception of the "MDS rumble" being reduced to the levels they experienced could also "Possibly" be the difference in the vehicle structure. The difference is the new Ram with Dampers vs. the old Ram without and also the Grand Cherokee SRT8 with a 6.4l vs an older Ram with a 5.7L, all completely different animals.
The Critic had previously stated this about his Ram, "To be fair, mine is almost unnoticeable as it currently is.", and as OVERKILL mentioned to him, his Ram has the frame-mounted Dampers that Skippy's is not equipped with. Right there, OVERKILL mentions a variable when it comes to the Ram vs Ram MDS rumble.
So using The Critics experience, a Ram with dampers is almost unnoticeable as is, while the older Ram is very noticeable,... I know this because I drive one. Therefore the same amount of reduction in "MDS rumble" using either oil may take the new Ram to "imperceptible" while taking the older Ram to "noticeably smoother" with the dampers and structure being the variable causing the difference in perception.
I guess what I should have stated is that it is "possible" that the special blend with the Supercar 0w40 additive is not specifically needed to achieve the "same level" of reduction in "MDS rumble".
Either way, you're correct, I really don't know for sure, I'm just forming an opinion based on what I've read and my thoughts on the differences in vehicles. More experimentation is called for.

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