This is a question for cold weather starts. Nebraska cold, -5F with -25 windchill,not Florida winter of 75F or Texas at 45F. From the Amsoil chart online,I got the impression that a very low CCV number was good for cold weather starts,and one of the best out there that I can purchase locally is Havoline synthetic as it's CCV is on par with Amsoil. My car is a 2006 Acura that takes 5W-20. All the newer Honda and Acura's specify 0W-20. Now after trying Super Tech synth. and the Havoline I've wanted to try the Pennziol natural gas. However, with at least a month or two of very cold weather left and my oil change coming due, I considered getting the 0W-20 instead the 5W-20 but the 0W has much worse CCV numbers than the 5W-20, per the Penzoil website and the information found there. I don't really understand how or why a 0W has worse cold cranking properties than a 5W, but that is per the ccv numbers that they have listed for those two grades. any suggestions or ideas as to why this is and which would be better for these freezing cold starts?