Took poly for LE agency and after the test I was told to wait in the lobby. About 20 minutes later I was brought back in and told I was deceptive in one of the questions. I was then given the "post-test interrogation" but I stood my ground and admitted to nothing because I have nothing to admit. 

I then thought I was done as I failed the test so I was ready to leave and the examiner said they would schedule a re-test and focus on that one question and area of deception. 

1 - Why would they re-test me if I "failed" the first time? 
2 - Should I go back and re-test or is my fate sealed and it's just a game to them?
3  - Can I "pass" the second time and does it invalidate the first test?

I am just confused why they would even call me back to re-test?

So in reality the polygraph examiner lied to me and told me that I was deceptive and needed to be re-tested to find the exact area of deception. 

Why would it matter what exact area it was? As I would have been disqualified if they believed I lied. In reality, like mentioned here, the test was inconclusive. That makes more sense now. 

If I understand the process correctly, a control question is a question the examiner assumes you are going to lie on. For example, "have you ever hurt a loved one, besides what we talked about?" When you answer "NO", the examiner uses this control question as a baseline because he knows you are lying on that question. Then the real question, "have you ever stolen money from your workplace?" is where they compare the control questions to the real question.

This whole poly test is so ridiculous and based in psuedo-science and flawed. Might as well go back and measure peoples skulls and feel for indentations to determine how smart they are and how healthy they are.