For now. . . don't worry about it. Find out what works best for you.
Instinctive is a way that you train your brain to see the whole picture and you hold the bow / arrow in a certain manner based upon your brain's reaction. Although your eyes see everything, just as a camera does, your have the ability to focus on certain aspects, and that is the target of choice.
Snap shooting is what was coined for those folks that seemingly don't aim (they do) but release as soon as the arrow gets back to the anchor.
By taking some of the power away from your brain, you are seeing the whole picture, and you are aware of the target as well as the location of the arrow tip in relation to the target. You have learned that at X yards you need the tip to be compared to the target of choice. That is when you start getting into that split vision thing.
By putting even more thought on the gap of the arrow point vs the target of choice, you get into true gap shooting.
SHooting three under allows the arrow to normally be closer (higher up ) to the eye and allows you to see the arrow better as well as makes for smaller gaps, up to point on.
By moving your anchor point up and down you face, you can move the impact point of the arrow without changing the gap (point on, or nearly so).
You can do nearly the same by moving your fingers below the arrow nock and string walking ( moving down a determined number of twists for each distance.
All work. All are good. It is my opinion that for most folks, every time you add an aide (front sight / point, rear sight, release etc etc) you make it potentially easier to be more accurate and repeatable. This is not to say that you are inaccurate using totally instinctive shooting.
At least, I think so
CHuckC