With the Auto-aim assist Skyrim controls some "dead zone of the deviation" and implicitly changes the projectile's fall point to count hit in a target, even if it should fly by (miss). Despite the false hits, the Auto-aim is still necessary because it is responsible for "drawing" the projectile's flight trajectory in correct angle in according with the crosshair position. Auto-aim fits well the inexperienced shooters (it working by default in Vanilla).
The AIM FIX mod offers two ways of the crosshair handling which can be combined:
1. Dynamically switch the aiming assist tweaks (more false positive hits along with a more precise crosshair).
2. Dynamically apply the aiming offsets to change a bias between the invisible aiming point and the crosshair position.
I personally don't use even a Vanilla Auto-aim after I been able to hit some bandit using the bow at very far distance simply by pointing the crosshair on him and even without a proper vertical angle of aiming. I do not force you to do the same, it's up to you, there is an MCM option to provide a flexible choice.

AIM FIX will toggle values of "fMagnetismLookingMult" and "fMagnetismStrafeHeadingMult" dynamically along with the Aim Assist auto-switches in order:
When the Aim assist (Proper aiming) is ON: fMagnetismLookingMult and fMagnetismStrafeHeadingMult is getting default Skyrim values. Reason: these parameters are not affecting the aiming until you disable the Aiming assist (aka Proper aiming) in MCM, and eventually Skyrim's Auto-aim works better when they set to default values.
When the Aiming assist is OFF: the Skyrim's auto-aim assist will become completely disabled and does not control projectiles flight trajectory any more so that a zeroed magnetism is become matter > without Aim assist parameters are toggling to this state: fMagnetismLookingMult = 0.0 and fMagnetismStrafeHeadingMult = 0.0

As for the tilt up angle parameters, the AIM FIX mod is overriding them (not dynamically, just once) so you need to tune them up in AIM FIX MCM directly as you want. They are in the Aiming Control MCM-section. See hints below when hovering them in MCM and you will see at the end of each hint's text if there any Skyrim parameters is affected. In MCM under the Projectiles Tilt Up Angle header you will find such parameters:
Arrows (1st Person) changes the f1PArrowTiltUpAngle
Arrows & Spells (3rd Person) changes the f3PArrowTiltUpAngle
Bolts (1st Person) changes the Aim Assistf1PBoltTiltUpAngle[/b]
You may didn't know, but the "f3PBoltTiltUpAngle" parameter does not exist in Skyrim at all and it will don't work whatever values you use for it in Skyrim.ini. To control vertical deviation for bolts in 3rd person you can use the "Aiming Offsets Archery" MCM-section and correct
vertical position of the crosshair for crossbow in 3rd person individually.

Skyrim.ini parameters which will be managed (overridden) by the AIM FIX mod, so it is recommended to remove them from your config:
(in MCM you can find them in hints appearing below then you hovering mouse pointer at the options)
[Combat]
f1PArrowTiltUpAngle
f1PBoltTiltUpAngle
f3PArrowTiltUpAngle
[Camera]
fDefaultWorldFOV
fMouseWheelZoomIncrement
fMouseWheelZoomSpeed
fOverShoulderCombatAddY
fOverShoulderCombatAddY
fOverShoulderPosX
fOverShoulderPosZ
fPitchZoomOutMaxDist
fShoulderDollySpeed
fVanityModeMaxDist
fVanityModeMinDist

Proper aiming
Any of "No magic ninja NPC dodge" mod

AIM FIX mod have a dynamic control over the similar to functionality of these mods.

AIM FIX mod is compatible with any non-camera mod unless other mod hooks the same hotkeys and events, but since v2.1 AIM FIX provides the Advanced Compatibility MCM-section where you can disable some parts of conflicting functionality.
Currently the MCM does not activate if you play a non-vanilla start, I will improve this mechanism and release a small update ASAP. Thank you for understanding that the development is not easy process.

> Intro scene compatibility?
Compatible. If you start a new game the AIM FIX will be inactive (including MCM) until you escape Helgen. After you get out of cave and Alduin will fly far away (the Unbound quest completes) you will see the AIM FIX welcome message, the camera will apply its default settings, and the MCM will become active.
For alternative start and other mods that replacing the vanilla start sequence please use patch (available in the Downloads section as optional file).
If you already have an alternative start mod but want to start a new playthrough from the vanilla intro sequence Unbound quest (Helgen) you better to:
- disable the Alternative start mod and all its patches for other mods if you have ones;
- disable the AIM FIX patch for non-vanilla start, leaving the main AIM FIX mod enabled.
When you do so, you can enable main AIM FIX mod and start new game. AIM FIX will automatically goes into its standby mode and wait until you finish the Unbound quest. During Helgen you will have a vanilla camera. After exiting the cave the AIM FIX camera will apply, MCM will turn ON, and you will be able to adjust settings as you prefer.

> Fully compatible mods which not require special setup or a patch:
Enhanced Camera
SkyHUD
Simple Crosshair
if you have any custom UI or camera mods compatible with the AIM FIX to report about, please tell me to update this list.

> Partially compatible mods which may require a special setup or a patch:
Immersive First Person View limitations: the AIM FIX mod will not apply the 1st person crosshair offset instantly, but it will apply the 1st person offset while holding the attack button. When the attack button is released during IFPV cam the offset will revert to a 3rd person value since IFPV technically does not activate 1st person view (camera remains in 3rd person being at the character eyes level). Also the camera view auto-switches for will not activate because IFPV makes 3rd person always active.
Immersive HUD (iHUD). Compatibility patch available here in the download section. See instructions below if you want to use SkyHUD and iHUD along with the AIM FIX.
Customizable UI Replacer and its depencies. See instructions below if you want to use SkyHUD and iHUD along with the AIM FIX.
Archery Gameplay Overhaul - to make AGO + AIM IFX work together, you must turn off AGO's bow crosshair and bow camera features.
SkyTweak - Postings by GrimyBunyip on reddit and in the STEP Forums, as well as personal experience:
FIRST go into AIM FIX mod MCM and set it up all the way you want. Exit the AIM FIX MCM but do not leave the System Menu and without touching SkyTweak at all do save your game then. After you save, you can open SkyTweak MCM. It should have and keep the values you set for the AIM FIX. Make sure you save after confirming all values in SkyTweak, and SkyTweak will always have the correct values. If you ever need to change a value later, just make sure you save your game before you open SkyTweak. Save before working in SkyTweak. Always change settings in SkyTweak last.
Scrolling Speed - compatiblity solution for AIM FIX + Scrolling Speed:
after the AIM FIX has initialized first time all you need to do it's go into the Scrolling Speed MCM and simply reassign all hotkeys again. Each next game reload will not cause the override anymore. So no need to sacrifice a part of AIM FIX functionality by disabling its "Intercept Camera Zoom In/Out Keys" option.


> Incompatible mods:
Customizable Camera

Enhanced 3rd Person Camera
Any other scripted camera mod is incompatible (SKSE camera mods fully compatible mostly)
________________________________________________________________________________

> Note on iHUD + SkyHUD + Customizable UI Replacer + AIM FIX compatibility:
Please use your mod manager's mods list (not plugins list) and place/activate them in appropriate order:
0. <any other non-UI mods>
1. SkyUI
2. iHUD
3. <other minor UI mods>
4. SkyHUD with its own iHUD compatibility patch (incl. its own iHUD patch)
5. Customizable UI Replacer (if you prefer it too)
6. iHUD compatibility patch for AIM FIX (from AIM FIX download page)
7. <any other non-UI mods>
8. AIM FIX mod
9. <any other non-UI mods>

> Note on installation of a custom UI mod on a saved game where the AIM FIX is already active:
1. In MCM: before installing the custom UI, in any activity MCM-section please do enable "Stealth Meter Lock (Custom UI)" MCM option
- this will make the AIM FIX to absorb custom stealth meter position at next game load. After that save the game and exit from Skyrim to desktop.
2. In mod manager: and install custom UI (e.g. SkyHUD, Customizable UI Replacer, etc).
3. In Skyrim's main menu: load you saved game and the AIM FIX will absorb new stealth meter position.
This actions no need to be performed in case if you are activating all mods at once by loading a clean save or starting a new game.

Adjusting the aiming offsets is to to make them work over the rest MCM settings.
1. First do set up all MCM settings at your personal taste (camera, Auto-aim, etc).
2. Only after all MCM settings was set do start adjusting the archery/magic offsets which you gonna use (for example: not using 1st person camera to shoot? - no need to adjust) to make them work over the rest settings you made.
Repeat the offsets correction when:
- you changed ranged camera settings, FOV or vanity distance;
- you toggled the Auto-aim assist for archery or magic;
- the crosshair goes crazy again after another new mod activated in your current saved game.

> How to play using GamePad with Smooth camera follow feature working (solution by jeffbk0710):

Of course, alternatively you can use any mod, that allows you to assign keyboard keys to the left stick movement.

> How much intensive is the script load?
This mod is very script intensive but NOT script-heavy. It hooks many events and controls and may not suit a script load purists because it is impossible to achieve zero-load and maintain so many dynamic functions. So only some optimizations from ver to ver. AIM FIX mod is always well optimized.

> Q: Why sometimes the camera does not switch on wheel scroll between 1st/3rd person when I ranged?
A: This is not a bug - its a normal game behavior when you have locked wheel zoom. Explanation: the locked wheel zoom option makes the values of the minimum and maximum vanity distance parameters (skyrim.ini) to be equal, but the mouse wheel scrolling is continue to work and not being applied because the min and max vanity has the same values. For example, in the 3rd person with drawn bow and locked wheel zoom, each time you try zoom out more and more by scrolling the mouse wheel, your zoom value being remembered by the game but not applied (virtually). As a result, to go back into 1st person you need to scroll the mouse wheel forward same number of times you scrolled it backwards before.

> Possible issue: the aiming offsets does not apply no matter how far they shifted via MCM settings
Problem with AIM FIX offsets is always lies on other mods - UI replacers and any mods which is controlling the crosshair appearance via script.
Solution 1. Exclude current saved game. Try load all your mods along with the AIM FIX on a clean save (saved game without mods) or start a new game. Wait some time for first initialization of all mods and see how AIM FIX apply the offsets. If all works well, then previously played save was broken.
Solution 2. Exclude interfering mods. For a start, make your Skyrim almost Vanilla: turn off all the mods in your load order and enable only AIM FIX and its decencies (SkyUI, SKSE, some general fixes can be enabled of course). Load a clean save or start new game. If AIM FIX works well, then you have to enable you r mods one by one (or by little groups) and check a clean game every time.

> Possible issue (legacy): AIM FIX is installed on clean save or non clean (with other mods already) - MCM does not appear, mod does not work.
Explanation. If the smooth camera not following or the view does not go up after crouching then AIM FIX is not working.
Solution 1. Simply exit into the main menu and load same game again. After loading try to not move you character. After appearing of the AIM FIX "hello" message (4 secs) MCM should appear.
Solution 2. Try load previous save where AIM FIX or 3PCO/3PCO++ was already installed. If the
smooth camera is following and the view goes up after crouching, then AIM FIX is working. Just do reset to defaults and then adjust settings at your personal taste. It must be a best way if you not want to start a
new game.
Solution 3. Try load all your mods along with the AIM FIX on a clean save (saved game without mods) or start a new game - it works
95%.

> Possible issue (legacy): MCM does not appear on first mod load (clean save/new game) but mod works (smooth camera is following)
Solution 1. All you have to do it's simply open the MCM mods list, close it, wait 5-10 seconds in game and open MCM again. 100% working solution for this specific case.
Solution 2. If the smooth camera not following or the view does not go up after crouching then something goes wrong. You have to load other saved game. Everything will be fine 100% if you load saved game where already was running AIM FIX (previous version of example). Just do reset to defaults and then adjust settings at you personal taste.
Solution 3. If you don't have such save (with AIM FIX or 3PCO installed previously), then try load a clean save (without mods) or start a new game to make your mods set to initialize along with AIM FIX - it works 95%.
Solution 4. Bad luck again? (Oh! Come on!) In this case you have to turn off all the mods in your load order and enable only AIM FIX and its decencies (SkyUI, SKSE, some general fixes can be enabled of course).

> Note about the aiming offsets adjustment for magic equipped in both hands:
Please take into account that AIM FIX mod not recognize specific spell in each hand, so it in case of a long range spell fire and healing by other hand at once, then AIM FIX will apply the crosshair offset for dual casting. Not a big deal (I hope), but mages must remember.