How exactly does AudioClip.Create() work?

I'm using AudioClip.Create() to create procedural tones. Using the example provided it is functional and I've been able to implement my own tones, but I want to take it further and I'm not understanding what the callback functions are doing or why I should be using this function at all!

My first question is in regards to the 'frequency' argument within Create(). Why does it accept a frequency if you make the frequency yourself inside the OnAudioRead() callback function? What baffles me further is that even though I'm overriding the frequency (or so I thought) within the OnAudioRead() using a standard sine wave input for the audio data, the frequency argument seems to affect the pitch.

OnAudioRead() appears to be called 12 times when using AudioClip.Create() with the following parameters: ("Sine Tone", 44100, 1, 44100, false, false, OnAudioRead, OnAudioSetPosition) Is there any reason that it needs to be called 12 times? I think there's something I don't understand about the callbacks in general. The 'position' integer also makes little sense to me. What is this meant to be doing!?

Here's the code for reference:

 using UnityEngine;
 using System.Collections;
 
 public class ToneGenerator : MonoBehaviour {
     
     private AudioClip[] tones;
     private AudioSource audioSource;
     private int position = 0;
     private int sampleRate = 0;
     private float frequency = 0;
 
         void Start ()
     {        
         //Audio properties
         audioSource = gameObject.AddComponent<AudioSource>();
         audio.volume = 0;
         audio.loop = true;
         
         GenerateTones();
     }
 
     void GenerateTones () 
     {
         tones = new AudioClip[4];
         
         //Generate the tones
         sampleRate = 44100;
         
         frequency = 440f;
         tones[0] = AudioClip.Create("Saw Tone", 44100, 1, 44100, false, false, OnAudioRead, OnAudioSetPosition);
         frequency = 300f;
         tones[1] = AudioClip.Create("Saw Tone", 44100, 2, 44100, false, false, OnAudioRead, OnAudioSetPosition);
         frequency = 200f;
         tones[2] = AudioClip.Create("Saw Tone", 44100, 2, 44100, false, false, OnAudioRead, OnAudioSetPosition);
         frequency = 500f;
         tones[3] = AudioClip.Create("Saw Tone", 44100, 2, 44100, false, false, OnAudioRead, OnAudioSetPosition);
     }
     
     void OnAudioRead(float[] data) 
     {
         for(int i = 0; i < data.Length; i++)
         {
             switch (wave)
             {
             case waveType.Sine:
                 data[i] = Mathf.Sin(2 * Mathf.PI * frequency * position / sampleRate);
                 break;
             case waveType.Sawtooth:
                 data[i] = (Mathf.PingPong(frequency * position / sampleRate, 0.5f));
                 break;
             case waveType.Square:
                 data[i] = Mathf.Sign(Mathf.Sin(2 * Mathf.PI * frequency * position / sampleRate)) * 0.5f;
                 break;
             case waveType.Noise:
                 data[i] = Mathf.PerlinNoise(frequency * position / sampleRate, 0);
                 break;
             }
             position++;
         }
     }
     
     void OnAudioSetPosition(int newPosition) 
     {
         position = newPosition;
     }
 }

Thanks for any advice or resources!