Centipoise is the measure of Thickness. While Viscosity is the measure of Resistance to Flow. So, the heavier oil will stay at a higher Centipoise throughout the temperature range. Going to lower weights decreases the Centipoise within the lower ambient temps'. Once the engine reaches operating temp's the Weight of the oil needs to continue its job at 180-210 degrees approximately. At operating temps' the viscosity of all oil goes way down.
The cgs physical unit for dynamic viscosity, the poise (P), is also named after Jean Poiseuille. It is more commonly expressed, particularly in ASTM standards, as centipoise (cP) since the latter is equal to the SI multiple millipascal seconds (mPa. s). For example, water at 20 °C has a viscosity of 1.002 mPa.