You mean the paperwork after the inteview? If yes, that has nothing to do with US Embassy. They were done with US Embassy at the end of December. However, it took them 2 months to complete the required process for leaving the country. And, that's very country-specific information. So, there is no reason to generalize it for other countries.Anahit,
You mentioned that the post interview for your sister was quite tough, what did you mean by post interview administrative processing?