This is an existing value you have to provide to the calculator (in the "Sensitivity 1" field of the input game), it is not being calculated. You can change it from the default of 3 to perhaps increase the accuracy, as the game lacks a lot of decimals. I.e. try to set it to 1, 1.2, 1.3 etc to see if the discrepancy (as indicated by the color, red in your screenshot) gets better.