Third post this week. Must really be bored. In the "old" days, it seems that a wide spread in multi viscosity was bad because of all of the VI improvers. Now it seems that you guys like the "wide spread" oils. For instance, 10w30 was better than 10w40 because it(30) had less VI improvers(supposedly). Now you guys are recommending 0 and 5w40. What changed?