My take on this, GM is blending dino with synthetic for a reason.
It may offer better shear characteristics and possibly bond well with valve train & seals especially in the VVT engines. What percentage of dino is in there is anyones guess.
If it is a third dino, a cost saving would sill be recognized and less carbon byproducts.
For my older 97 Pk Ave I blend my oils. One quart of High mileage 10w-30 and the rest synthetic. I also add one bottle of Lubegard blue bottle. My valve train quietens down big time with the lubegard bio engine treatment. LUBEGARD BIO-TECH Engine Oil Protectant
In my Jeeps limited slip differential I wont use synthetics. Lucas 85w-140 is in there, I want the gear thick and sticky oil in there. Sometimes I think synthetics become a little thin when real hot.