Bullet Spawn depends on frame rate.

Hello
I'm making a Bullet Hell Game. But I have trouble making the spawners Framerate Independent.
If I Pause and Frame Advance The spawners spawn more, But In Realtime it spawns less.
A clear Indicator that It depends on frame rate.
I Tried Time.deltaTime But that doesn't work.
Here's the Code Snippet In charge of the spawning:

 // Fire Bullets
         if (fireNumber >= rateOfFire)
         {
             SpawnBullet();
             fireNumber = 0;
             bulletCount++;
         }
         else
             fireNumber += Time.deltaTime;

My guess is that if the amount Time.deltaTime is bigger than the spawn rate it skips over them.
I can't just spawn more bullets if Time.deltaTime is bigger than the spawn rate because they would just be on top of each other.
This is a big problem for the game and I would appreciate any answers.

Edit: Full Script. Warning Messy and unreadable:

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class BulletSpawn : MonoBehaviour
 {
     //Spawn Controls
     public GameObject spawnObject;
     public float rateOfFire;
     public float bulletSpeed = 0.1f;
     public bool randomBulletSpeed;
     public bool aimAwayFromBoss = false;
     public Sprite Colour;
     public float offset = 0;
     public bool patterned = false;
     public int everyBullet = 10;
     public float waitTime = 100;
     public float speedAdd = 0f;
     public float curveTimeAdd = 0f;
     public int rotationOffset = 0;
     public bool spawningSpawns = false;
     public AudioClip clip = null;
     public bool lazer = false;
     public float lazerTime = 1;
     public float lazerWait = 1;
     public Animation playedAnimation;
     public moveObj_Aim aimer;
     public moveObj_RandomRotation randomRotation;
     public bool ignoreFirst = false;
     public bool randomOffset;
 
     public bool easeIn = false;
     public bool easeOut = false;
     public bool curve = false;
     public bool reSet = false;
     public float curveRate = 0.1f;
     public float curveTime = 1f;
     public float newSlow = 0.5f;
     public float[] changeTimes;
     public float[] rotationAdd;
     public float[] newSpeed;
     public float changeEase = 0.05f;
     public bool affector = false;
     public bool affectorEnter = false;
     public bool aimAtPlayer = false;
     public bool randomRot = false;
     public bool follow = false;
     public float changeSpeed = 0f;
     public bool destroyEnter;
 
     public float min;
     public float max;
 
     public GameObject objChange;
     public int rofChange;
     public bool ssChange = false;
     public float speedChange = 0;
     public float bSpeedChange = 0.1f;
     public bool homingChange = false;
     public bool homingCChange = false;
     public Color tintChange;
     public int offsetChange = 0;
     public AudioClip clipChange = null;
 
     public bool easeInChange = false;
     public bool easeOutChange = false;
     public bool curveChange = false;
     public float curveRateChange = 0.1f;
     public float curveTimeChange = 1f;
     public float newSlowChange = 0.5f;
 
     //Movement Controls
     public float speed = 0;
     public bool homing = false;
     public bool homingContinuous = false;
 
     float fireNumber;
     float bulletWait = 0;
     int bulletCount = 0;
 
     float originalSpeed;
     float originalCurve;
     float offsetCount;
 
 
     public Quaternion initialRotation;
     GameObject tempObj;
 
     // Use this for initialization
     void Start()
     {
         originalSpeed = bulletSpeed;
         originalCurve = curveTime;
         if (homing)
         {
             Vector2 dir = GameObject.Find("Player").transform.position - transform.position;
             float angle = Mathf.Atan2(dir.y, dir.x) * Mathf.Rad2Deg;
             angle -= 90;
             angle += rotationOffset;
             transform.rotation = Quaternion.AngleAxis(angle, Vector3.forward);
         }
         if (aimAwayFromBoss)
         {
             Vector2 dir = GameObject.Find("BossInitialPosition").transform.position - transform.position;
             float angle = Mathf.Atan2(dir.y, dir.x) * Mathf.Rad2Deg;
             angle -= -90;
             angle += rotationOffset;
             transform.rotation = Quaternion.AngleAxis(angle, Vector3.forward);
         }
         fireNumber = rateOfFire;
         //offset += (float)Random.Range(-1f,1f);
         offsetCount = 0;
     }
 
     // Update is called once per actual frame
     void Update()
     {
         //Move if Possible
         gameObject.transform.Translate(new Vector2(0, speed), Space.Self);
 
         if (offsetCount < offset)
         {
             offsetCount += Time.deltaTime;
             return;
         }
 
         if (homingContinuous)
         {
             initialRotation = gameObject.transform.rotation;
             Vector2 dir = GameObject.Find("Player").transform.position - transform.position;
             float angle = Mathf.Atan2(dir.y, dir.x) * Mathf.Rad2Deg;
             angle -= 90;
             transform.rotation = Quaternion.AngleAxis(angle, Vector3.forward);
         }
 
         if (patterned && bulletCount >= everyBullet)
         {
             bulletWait += Time.deltaTime;
             if(bulletWait >= waitTime)
             {
                 bulletCount = 0;
                 bulletWait = 0;
                 bulletSpeed = originalSpeed;
                 curveTime = originalCurve;
             }
             else
                 return;
         }
 
         // Fire Bullets
         if (fireNumber >= rateOfFire)
         {
             SpawnBullet();
             fireNumber = 0;
             bulletCount++;
         }
         else
             fireNumber += Time.deltaTime;
 
         if (homingContinuous)
             gameObject.transform.rotation = initialRotation;
     }
 
     private void LateUpdate()
     {
         if (fireNumber >= rateOfFire)
         {
             if (randomRotation != null)
                 randomRotation.RandomRotation();
         }
     }
 
     void SpawnBullet()
     {
         tempObj = Instantiate(spawnObject);//ObjectPooler.SharedInstance.GetPooledObject(spawnObject.name);
 
         tempObj.transform.position = transform.position;
         tempObj.transform.rotation = transform.rotation;
         //tempObj.SetActive(true);
 
         if(aimer != null)
             aimer.Aim();
 
         BulletManager.sharedInstance.GetSpawnSound(clip).Play();
         if(playedAnimation != null)
             playedAnimation.Play();
         if (spawningSpawns)
         {
             BulletSpawn bulletSpawn = tempObj.GetComponent<BulletSpawn>();
             bulletSpawn.spawnObject = objChange;
             bulletSpawn.rateOfFire = rofChange;
             bulletSpawn.spawningSpawns = ssChange;
             bulletSpawn.speed = speedChange;
             bulletSpawn.bulletSpeed = bSpeedChange;
             bulletSpawn.homing = homingChange;
             bulletSpawn.homingContinuous = homingCChange;
             bulletSpawn.offset = offsetChange;
             bulletSpawn.clip = clipChange;
             bulletSpawn.fireNumber = tempObj.GetComponent<BulletSpawn>().rateOfFire;
 
             if (easeInChange || easeOutChange || curveChange)
             {
                 bulletSpawn.enabled = true;
                 bulletSpawn.easeIn = easeInChange;
                 bulletSpawn.easeOut = easeOutChange;
                 bulletSpawn.curve = curveChange;
                 bulletSpawn.curveRate = curveRateChange;
                 bulletSpawn.curveTime = curveTimeChange;
                 bulletSpawn.newSlow = newSlowChange;
             }   
         }       
         else if (!lazer)
         {
             if (randomBulletSpeed)
             {
                 RandomizeBulletSpeed();
             }
             tempObj.GetComponent<Bullet>().speed = bulletSpeed;
             tempObj.GetComponent<Bullet>().ignoreFirst = ignoreFirst;
             if(Colour != null)
                 tempObj.GetComponent<SpriteRenderer>().sprite = Colour;
         }
         else if (lazer)
         {
             tempObj.GetComponent<Lazer>().waitTime = lazerWait;
             tempObj.GetComponent<Lazer>().time = lazerTime;
             tempObj.transform.parent = gameObject.transform;
             tempObj.transform.localRotation = Quaternion.identity;
         }
 
         if (easeIn || easeOut || curve || reSet || affectorEnter || affector)
         {
             tempObj.GetComponent<BulletEffects>().enabled = true;
             tempObj.GetComponent<BulletEffects>().easeIn = easeIn;
             tempObj.GetComponent<BulletEffects>().easeOut = easeOut;
             tempObj.GetComponent<BulletEffects>().curve = curve;
             tempObj.GetComponent<BulletEffects>().curveRate = curveRate;
             tempObj.GetComponent<BulletEffects>().curveTime = curveTime;
             tempObj.GetComponent<BulletEffects>().newslow = newSlow;
             tempObj.GetComponent<BulletEffects>().reSet = reSet;
             tempObj.GetComponent<BulletEffects>().changeTimes = changeTimes;
             tempObj.GetComponent<BulletEffects>().rotationAdd = rotationAdd;
             tempObj.GetComponent<BulletEffects>().newSpeed = newSpeed;
             tempObj.GetComponent<BulletEffects>().initialSpeed = bulletSpeed;
             tempObj.GetComponent<BulletEffects>().time = 0;
             tempObj.GetComponent<BulletEffects>().changeNumber = 0;
             tempObj.GetComponent<BulletEffects>().finished = false;
             tempObj.GetComponent<BulletEffects>().affectorEnter = affectorEnter;
             tempObj.GetComponent<BulletEffects>().affector = affector;
             tempObj.GetComponent<BulletEffects>().aimAtPlayer = aimAtPlayer;
             tempObj.GetComponent<BulletEffects>().randomRotation = randomRot;
             tempObj.GetComponent<BulletEffects>().followDirection = follow;
             tempObj.GetComponent<BulletEffects>().changeEase = changeEase;
             tempObj.GetComponent<BulletEffects>().changeSpeed = changeSpeed;
             tempObj.GetComponent<BulletEffects>().destroy = destroyEnter;
         }
 
         bulletSpeed += speedAdd;
         curveTime += curveTimeAdd;
     }
 
     void RandomizeBulletSpeed()
     {
         bulletSpeed = Random.Range(min, max);
     }
 }