Overview or Conclusion?

I just want to ask and to clarify about the structure in Task 1.  I have seen different variations of the structure from different teachers of IELTS. Scott's English follows the Introduction, Paragraph 1, Paragraph 2 and then Summary or Conclusion format.  Other teachers will say that the overview should be written right after the Introduction is made.  So I am quite puzzled as to which is the best to garner a higher band score from both styles? 

Thanks in advance!

Peter