Mouse sens isn't a mystery or a black art. It's either the correct amount of yaw/pitch per x number of counts sent from a mouse, as per the method you are choosing to match, or it isn't. "Feel" is irrelevant to that process.
This just sounds like you haven't yet decided what the best way for you to match ADS is for your own preference, but you should also check that your mouse software doesn't have an automatic profile for a game that has a different dpi set.
You should also note that different games have other mechanics that can make aim feel different, such as the camera viewport position in both z axis and y axis vs it's pivot point (some games tie the camera physically to a character models head which then moves as per the character animations, which usually sets the camera slightly forward of its pivot point, others position the camera and pivot directly within the character's centre mass vertically and the character model just bobs around it), and also strafe movement speed can play a huge part because people rarely aim when completely stood still. Some games also scale during ADS transitions differently, and since you don't usually aim then turn, but rather aim *and* turn simultaneously, this can also massively change how aiming feels even at exactly the same sensitivity.
The calculator can match the mouse sensitivity, FOV and resolutions in a multitude of fashions you can select, but not all the other facets of the game - you still need to learn / adapt to play the "new game" somewhat.