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 potential of the game engine for the ballistics is very high comparing to many other AAA games (they mostly have very poor physics and letting players to kill everything by the blind click), but the Bethesda developers sought to make the game interesting, first of all, for beginners and console fans, so the ranged mechanics was sharpened only for the auto-aim assist.
If you purposefully prefer to play without the vanilla Auto-Aim assist then the ranged combat with the AIM FIX mod will be much better. You can always see for yourself how the crosshair will shift in all four directions without the AIM FIX aiming offsets any other mod that disables the Auto-Aim Assist (unofficially ported Archery Gameplay Overhaul, Disable Auto-Aim, etc). With the AIM FIX aiming offsets you will able to minimize the crosshair shifting from four to only two directions in relation to different distances to the target. it is possible to achieve only if you follow the
You can achieve maximum accuracy of shooting for 3rd person without the auto-aim only by correctly setting the camera, which is shown in the Tutorial movie. If you don't understand the English language you can always enable subtitles and Google will generate it for you on selected language.
Thus please never even think that AIM FIX makes the ranged combat without the auo-aim worse ;)

If you using a gamepad then better stick with the auto-aim assist enabled, besides in the AIM FIX mod it tweaked better than vanilla (similar to Proper Aiming mod).
Disabling auto-aim assist 100% requires KB+mice and some strong desire to have a hardcore difficult archery, but very realistic.
In case if you really want to disable the auto-aim assist you have to study how the game mechanics works without the auto-aim, and you will have to get use to some game engine limitations, as described below (please read the rest Q&A). Also without the auto-aim you definitely should adjust the crosshair position using the Aiming Offsets feature of the AIM FIX mod.
Also if you are a very experienced shooter, then you should disable the auto-aim and you will see how actually accurate you are.

The crosshair will correspond to the projectiles flight trajectory at 100% only for a fixed distance, that you used for adjusting the aiming offsets and this is not AIM FIX mod fault.
Here it is important to open your understanding for such mechanics without the in-game auto-aim assist:
the departure angle of the arrow (or magic projectile) will always strictly correspond to the angle of the animation of the bow rotation in the hands or the character itself. And the animations, especially custom ones, do not initially coincide with the crosshair position.
First you calibrate the crosshair for exact distance that you yourself consider as a typical for entering into a ranged combat (I always use 10 character steps from a target). The mechanics of Archery in this case will be this:

• The closer an enemy will approach (closer than the calibrated distance), the more left the arrows will fly (when the character is on right side of the screen).
• The further an enemy than the calibration distance for which the crosshair is adjusted, the more right the arrows fly.
  

This gameplay mechanics are very simple, and it is the purest limitation of the game engine, with which you need to be reconciled. And even this limitation can be reduced to real shooting from a real bow: IRL the bow deflects the arrow to the side when releasing (fact).Thus using the AIM FIX offsets along with NOT using the in-game auto-aim is the only way to get an interesting and challenging game, where the accuracy depends on the player.

The Auto-Aim assist function is initially included in the game by default, for example, to ease aiming when playing with a gamepad, and also to REPLACE an actual flight trajectory of the arrows on a surrogate trajectory, so that the arrows always hit the crosshair, regardless how is the bow turned in the hands or the character himself. It is, of course, good that the crosshair always works well, but there is one side effect: almost all misses are counted as hits by the game. You can aim next to the bandit's ear, and you will hit him right between the eyes (here is a random example from YouTube). You can even aim above or much below the enemy and miraculously hit him in the chest (!), etc. By the way, even taking into account all the above, the crosshair can go crazy when installing custom animation mods.

Yes, most of the player who doing that like to play harder and more realistic way, but while the in-game auto-aim assist is enabled disabled crosshair is useless. Those who think that they are playing with realistic and sophisticated shooting, do not actually shoot as well as they see it - it's just the game does the trick for them, even on the Legendary level of difficulty.
The other side of this preference: when both auto-aim and crosshair is disabled, you will definitely get hardcore realistic archery, but unfortunately also you will get an invisible aiming point that jumps around affected by the engine limitations and other mods (animations for example). Since the crosshair is hidden, you will never see these deviations to compensate them during aiming, so you will get a four-directional aiming point deviation instead of two-directional achieved with the aiming offsets feature of this mod. Of course what's better for you is up to you, especially when you know what you get.
So, to get a hardcore realistic archery with two-directional aiming deviation instead of four-directional, I recommend to always use the crosshair even if you don't prefer to use it: you can simply make the crosshair look as a smallest dot and make it transparent (almost invisible). For example, Immersive HUD mod allows to control the crosshair transparency (future versions of AIM FIX mod will do the trick too), and for a dot crosshair you can install, for example, SkyHUD mod.

Because for a novice player in the game as such, will be difficult without the auto-aim assist. Not everyone prefers to tweak the MCM, and some even play just for fun and rest, which is not a crime, right? ;) Therefore, by default, the AIM FIX mod offers a tweaked auto-aim assist and basic offsets for it (similar to Proper Aiming mod), so those who playing, for example, with a gamepad, may do not worry about any difficulties that are not realizable for gamepads (gamepad always looses to a mice in accuracy and reaction).

Naturally, this does not mean that it is impossible to do that. In order to develop a dynamic crosshair offsets application mechanism that will be capable to work for different distances, I first need to develop this project further (at the source code level) in some directions. It took several months of continuous work to develop the AIM FIX mod, and I think you can imagine that this is not easy to perform. I breaking through the obstacles of development myself. If you like what I do, and you want to see the development of the project, you can always support this project by Endorsing, Voting, or donating.