time between wavs not work in if condition in unity

my code work fine but time between waves not work . i set this with different values but not work all things work well just this is my problem :(

using UnityEngine;
using System.Collections;

[System.Serializable]
public class Wave {
    public GameObject enemyPrefab;
    public float spawnInterval;
    public int maxEnemies;
}
public class SpawnEnemy : MonoBehaviour {

    public GameObject[] waypoints;
    public GameObject testEnemyPrefab;

    public Wave[] waves;
    public int timeBetweenWaves = 5;
    private GameManagerBehavior gameManager;
    private float lastSpawnTime;
    private int enemiesSpawned = 0;
    // Use this for initialization
    void Start () {

        lastSpawnTime = Time.time;
        gameManager =
            GameObject.Find("GameManager").GetComponent<GameManagerBehavior>();
    }
    // Update is called once per frame
    void Update () {
        // 1
        int currentWave = gameManager.Wave;
        if (currentWave < waves.Length) {
            // 2
            float timeInterval = Time.time - lastSpawnTime;
            float spawnInterval = waves[currentWave].spawnInterval;
            if (((enemiesSpawned == 0 && timeInterval > timeBetweenWaves) ||
                timeInterval > spawnInterval) && 
                enemiesSpawned < waves[currentWave].maxEnemies) {
                // 3  
                lastSpawnTime = Time.time;
                GameObject newEnemy = (GameObject)Instantiate(waves[currentWave].enemyPrefab);
                newEnemy.GetComponent<MoveEnemy>().waypoints = waypoints;
                enemiesSpawned++;
            }
            // 4 
            if (enemiesSpawned == waves[currentWave].maxEnemies &&
                GameObject.FindGameObjectWithTag("Enemy") == null) {
                gameManager.Wave++;
                gameManager.Gold = Mathf.RoundToInt(gameManager.Gold * 1.1f);
                enemiesSpawned = 0;
                lastSpawnTime = Time.time;
            }
            // 5 
        } else {
            gameManager.gameOver = true;
            GameObject gameOverText = GameObject.FindGameObjectWithTag ("GameWon");

        }

    }
}

dos not matter how much input for time between waves . if any one can help please help