In comparing Havoline and Motorcraft oils in the Amsoil comparison testing, of the 7 tests conducted there were noticeable differences in only 3 of them. Havoline was better in the "Thin Film Oxygen uptake Test", and Motorcraft was better in the "Cold Cranking Viscosity" and "Four Ball Wear" tests. Which of these tests are more important and which oil would you choose based on these results? Thanks! (I currently use Havoline and was considering switching to Motorcraft but the results of the "Thin Film Oxygen Uptake Test" where Havoline did much better concern me)