As G-Man says, 0W-20 oils can be blended from Group III base oils, which work very well with pour point depressants, so the formula can reach the cold pumping and cranking specifications. Honda, Toyota, and Castrol Edge 0W-20 oils are all Group III - I know because I had Dyson Analysis test them in the VOA section. It's a safe bet Pennzoil Platinum is Group III, too. I don't know about what addguy says, but it's entirely possible.