KCJeep,
I think Solarent commented sometime in the last several weeks that most companies use pre-approved additive packages in their blends. In this case it means that the dexos1 approved Pennzoil Platinum additive package with the current SN/GF-5 low moly and boron (~50 blend of Group II+ base oils/Group III+ (to include some GTL) base oils.
Interestingly, initially when the Pennzoil Syn-Blend was introduced, the published data showed a 13.0% NOACK, meaning it just met the upper dexos1 limit.
Now, I am guessing, that it's closer to 12.0% with a 50/50 blend of 9.3% (per PQIA) PP and 14.3% PYB.
So, it's anybody's guess how well the PP additive package will work with the blended basestocks, but my guess is, knowing SOPUS, pretty darn good!
Gary