There's a lot of games where you have to provide an existing sensitivity value to the calculator, since only one value can be calculated for each aim.
The issue with this game in particular is that the monitor distance coefficient affects hipfire, so we need to know two values before it can be calculated, the coefficient and the general mouse sensitivity. The main culprit is the lack of decimals though, if the game supported 6 decimals or more this wouldn't be an issue.