How to create GameObject (from prefab) at location of BoxCollider2D with rotation?

At the moment I have a rotated BoxCollider2D line (rectangular). It is created from a prefab. At the end of this BoxCollider2D (top right corner / bottom right corner) I want to Instantiate a new rotated BoxCollider2D from the same prefab.

At the moment I create the prefab, and they I try to get the coordinates of both BoxCollider2D's (from the previous line, and the new line). Using this I tried to Instantiate the second line using these positions, but something went wrong. When adding a debug to the locations I found out that they are both the same.

How can I get the correct coordinates to initialize the new line at the correct location? This script is linked to the previous line, which creates a new line when needed (which creates a new line again when needed).

Thanks in advance.

     GameObject newLine = Instantiate(line, Vector3.zero, Quaternion.identity);
     newLine.transform.eulerAngles = new Vector3(0, 0, Random.Range(-45, 45));

     //Variables for this line
     BoxCollider2D collider = (BoxCollider2D)this.gameObject.GetComponent<BoxCollider2D>();

     float top = collider.offset.y + (collider.size.y / 2f);
     float btm = collider.offset.y - (collider.size.y / 2f);
     float right = collider.offset.x + (collider.size.x / 2f);
     float left = collider.offset.x - (collider.size.x / 2f);

     Vector3 topRight = transform.TransformPoint(new Vector3(right, top, 0f));
     Vector3 topLeft = transform.TransformPoint(new Vector3(left, top, 0f));
     Vector3 btmRight = transform.TransformPoint(new Vector3(right, btm, 0f));
     Vector3 btmLeft = transform.TransformPoint(new Vector3(left, btm, 0f));

     //Variables new line
     BoxCollider2D newLineCollider = (BoxCollider2D)newLine.gameObject.GetComponent<BoxCollider2D>();

     float top2 = newLineCollider.offset.y + (newLineCollider.size.y / 2f);
     float btm2 = newLineCollider.offset.y - (newLineCollider.size.y / 2f);
     float left2 = newLineCollider.offset.x - (newLineCollider.size.x / 2f);
     float right2 = newLineCollider.offset.x + (newLineCollider.size.x / 2f);

     Vector3 topLeft2 = transform.TransformPoint(new Vector3(left2, top2, 0f));
     Vector3 topRight2 = transform.TransformPoint(new Vector3(right2, top2, 0f));
     Vector3 btmLeft2 = transform.TransformPoint(new Vector3(left2, btm2, 0f));
     Vector3 btmRight2 = transform.TransformPoint(new Vector3(right2, btm2, 0f));


     newLine.transform.position = new Vector3(btmRight.x + (btmRight2.x - btmLeft2.x) / 2, btmRight.y, 0);
     Debug.Log("btmLeft2x = " + btmLeft2.x + " btmRight2x = " + btmRight2.x);
     Debug.Log("btmLeftx = " + btmLeft.x + " btmRightx = " + btmRight.x);