Objects get small offset after Instantiate

After Instantiate i rotate the object with integer amount(90 or 180 ...). But when viewed from editor it has a rotation of 90.000001. This is a problem because I'm trying to trace the object with boxes, but this small rotation causes an extra row of boxes to appear and this breaks rest of the logic that depend on the accuracy of the box positions.

 void MatchExits(GameObject exit1, GameObject exit2)
     {     
         GameObject newPart = exit2.transform.parent.gameObject;
         Vector3 forwardToMach = -exit1.transform.forward;
         int correctiveRotation = (int)(Azimuth(forwardToMach) - Azimuth(exit2.transform.forward));
         newPart.transform.RotateAround(exit2.transform.position, Vector3.up, correctiveRotation);
       //  Debug.Log(Mathf.Round(correctiveRotation));
         Vector3 correctiveTranslation = exit1.transform.position - exit2.transform.position;
         newPart.transform.position += correctiveTranslation;
     }