How much time for consular processing?

[Werniman 0]

Hello,
My wife's employer is sponsoring her a green card (EB3). Currently she lives with a H1B in the USA. I (as a spouse) are included as a dependent in the I140. Because I still live in Germany, I should not do AOS, but consular processing. We have the following timeline:
11.April 2018: Petitions I140, I485, I765, I131 submitted.
May 30, 2018: biometrics appointment for my wife.
04.June 2018: Petition I-824 (consular processing) filed.
June 15, 2018: I765 + I131 were approved.
08 August 2018: On the advice of our lawyer, an I907 petition (Premium Processing) was filed.

It should therefore still be decided in August, whether the I140 petition is approved. If approved, the case will be sent from Texas to Philadelphia (Field Office).
According to the Processing Times ad here on your website, it can take an average of 292 days to complete the interview. That's a long time and I hope, of course, that it does not take that long.

My question is more about what comes next: the consular processing for me. As far as I know, this will only start when my wife's AOS has been successfully completed. Is that correct ? Then the petition will be sent to the NVC and from there to the consular in Frankfurt / Germany.
How much time does it spend for the entire consular processing task (between transfer from TSC to NVC until the interview in Frankfurt) ? Of course I searched the internet and the information is very different....from "3 months" to "2 years".