The new MRV # is still impressive ie slightly lower than the very light PP EURO LX 0W30.
(And the VI is over 200)
I wouldn't get excited about that, it just points to low visc bases being the primary blending ingredient. For example, XOM Chemical's 4cSt PAO, SpectraSyn 4, has an MRV of 5,000cP (!), a CCS Visc @ -30C of 910cP, a VI of 126 and a Noack ~14%. But we know this product is Group III based, not PAO, so:
While I unfortunately can't readily find MRV info for Yubase, if we look at two of their 4cSt offerings:
CCS @ -30C: 1,590
CCS @ -30C: 1,130
You'll note in both instances CCS is higher than PAO 4.
I'd wager Noack is right on the limit for the approvals the oil carries and that the base oil blend is primarily 4cSt with enough heavier GTL mixed in to get the Noack to that point. It's then treated heavily with VII's to get the visc, but the artifact of this is the low MRV and high VI.
If you look at the PAO-based Ravenol SSL 0w-40 for the sake of comparison you see:
Lower VI, higher MRV, both point to a heavier base oil blend. One that is still propped up with VII, but less of it.
SpectraSyn 8 has an MRV of 16,200cP, but SpectraSyn 10 is 36,650cP. Also, even SpectraSyn 8 would, by itself, exceed the CCS visc limits for the 0w-xx designation, as it is 4,800cP @ -30C.