C# sticking to Cube corners position (raycasting AI script)

I'm trying to use raycasting to make an AI script but I have to cast rays from the forward face. Right now I'm stuck as you can see below, I created colored sphere to see the actual positions i'm gathering. (Raycast origin)

So I tried to get the four corners of the forward face but as you can see, only half of it is actually working properly.

Here's my script: (I might have declared a few things i'm not currently using, sorry for the mess)

 using UnityEngine;
 using System.Collections;
 
 public class AIscript4 : MonoBehaviour {
 
      Vector3 DTarget;
      Vector3 DSource;
     float Swidth;
         MeshFilter mshFilt;
     Mesh gridMesh;
     GameObject[] goa=new GameObject[4];
     // Use this for initialization
     ArrayList Waypoints =new ArrayList();
     ArrayList goA=new ArrayList();
     void Start () {
         Transform nz=GameObject.Find ("TargetCube").GetComponent<Transform>();
     Vector3 SC=new Vector3(0.3f,0.3f,0.3f);
         
         
      mshFilt = (MeshFilter)GetComponent<MeshFilter>();
          gridMesh = mshFilt.mesh;
         DSource=transform.position;
         DTarget=nz.position;
         Vector3 fixdirection=DTarget-DSource;
         Debug.DrawRay(DSource,fixdirection,Color.red,555f);
     
 
         CreateDebugSphere(Vector3.one,Color.red,SC);
         CreateDebugSphere(Vector3.one,Color.yellow,SC);
         CreateDebugSphere(Vector3.one,Color.green,SC);
         CreateDebugSphere(Vector3.one,Color.magenta,SC);
     }
     int inc;
     
         void CreateDebugSphere(Vector3 pos,Color col,Vector3 scale){
     
         GameObject go = Instantiate(Resources.Load("DebugSphere")) as GameObject; 
         go.renderer.material.color=col;
         go.transform.position=pos;
         go.transform.localScale=scale;
         Debug.Log (inc);
         goa[inc]=go;
             inc+=1;
     }
     
     // Update is called once per frame
     void Update () {
         Vector3 br1=transform.TransformPoint(gridMesh.bounds.min);
         Vector3 br2=transform.TransformPoint(gridMesh.bounds.max);
     // Red
                 Vector3 DebugS1=new Vector3(
             br2.x,
             br1.y,
             br2.z
             );
    // Yellow
                 Vector3 DebugS2=new Vector3(
             br2.x,
             br2.y,
             br2.z
             );
    // Green
                 Vector3 DebugS3=new Vector3(
             br1.x,
             br2.y,
             br2.z
             );
    // Magenta
                 Vector3 DebugS4=new Vector3(
             br1.x,
             br1.y,
             br2.z
             );
 
         goa[0].transform.position=DebugS1;
         goa[1].transform.position=DebugS2;
         goa[2].transform.position=DebugS3;
         goa[3].transform.position=DebugS4;
     }
 }

I spent some time searching around for an answer but can't find anything anymore to help myself =\\

I would love some explanation why its acting like that!

To recapitulate, all spheres should stick to the sky blue face corners, in any rotation.

Eventually, I want to cast rays from the bottom of the blue face, two on the corners and one in the middle, towards a target.

Also, if you have better solution or better ways of doing AIs capable of moving and dodging static and/or non-static objects I'd love to know, although ultimately it will be for iPhones, so can't be too much CPU intensive.