spawn question

hello everyone
i have written a scene where platform spawned randomly until they reach
the max platforms i wanted
my problem is that i want to spawn a game object at the last platform
to be the finish point
how can i do that?
i’ve tried spaw script but the spawning isn’t doing well it’s always spawn at the first platform

my code is a little variation of the basic platform 2d game in the tutorials here
just for fun my end object is called stan

using UnityEngine;
using System.Collections;

public class spawnstan : MonoBehaviour {

public Transform stanpos;
public GameObject stan;


// Use this for initialization
void Start () {
    if (spawnst==spawnstmax)
    {
        Instantiate(stan, stanpos.position, Quaternion.identity);
        spawnst = 0;
    }
}

// Update is called once per frame
void Update()
{

}

}

this is the spawnplatform code

using UnityEngine;
using System.Collections;

public class spawnmaneger : MonoBehaviour
{

public int maxPlatforms = 5;
public GameObject Platform;

public float horizontalMax = 6.5f;
public float horizontalMin = 14f;
public float verticalMin = -6f;
public float verticalMax = 6f;

private Vector2 origin;
// Use this for initialization
void Start () {
    origin = transform.position;
    spawn();
}

void spawn()
{
    for (int i = 0; i < maxPlatforms; i++)
    { 
 Vector2 randpos = origin + new Vector2(Random.Range(horizontalMin,horizontalMax),Random.Range(verticalMin,verticalMax));
 Instantiate(Platform, randpos, Quaternion.identity);
 origin = randpos;
 if (i == maxPlatforms-1)
 {
     spawnstan.spawnst ++;
     spawnstan.spawnstmax = maxPlatforms-1;
     spawnstan.vector = origin;
 }
    }
}

}