When I look at the viscosity chart on the front page I can see where my oil is on the scale at 100c, but when I look at the visc at 40 c the number that I have for my oil doesn't make sense. 65.3 is base # for my oil,at 40c the uoa say 54.1(abn) 10.5 is the # for my oil at 100c , the uoa say 9.6 Now I can understand that my oil thin a bit at 100c. But if I looked at the chart for 40c 65.3 represent a 20w instead of a 10w ???????