[Vman455]

The way I've seen it used is 1 count = .001; so when that Chevy article references "12 counts saved" by smooth wheel covers, they mean a drag reduction of .012. Or, as Hotrod Magazine explains it: "The delta between Cd numbers is often referred to as "counts," or thousandths of a point, so the difference between a Cd of 0.250 and 0.200 is 50 counts."