H1B, H4 Visa

On 13th July I went to Mumbai embassy with my spouse and son to get my 7th year extension stamping. Though I am a chennai resident but I used emergency appointment (back to work category) option to booked the slot at Mumbai consulate.The waiting time was bit longer that day (4 hours) and interview took only 5 minutes. Mine was Visa renewal and she checked my current I797 and my previous visa that should be in the same company.She didn't ask any other documents and asked few questions regarding my job and weather condition of my present place.Few formal questions to my wife and son then she approved our visa.
The interesting point was I waited more than 2 hours inside the building until my number was called. I noticed most of the fresh H1B holders (90%) got the visa without any problem. I saw big smile from those guy after the interview. Most of the interview was less than 10 minutes.I don't think the person from south can book the slot at Mumbai consulate except emergency appointment option.Here we need to send the documents atleast 5 working days before the interview date and they would catch and redirect them to concern consulate. At the time of Finger print the lady in the counter asked me why I didn't book an emergency appointment at chennai instead of Mumbai and I explained the obvious reason (no slot available). All VO's were very nice and gentle. If you got married then go with your wife and the VO treated them very nicely and approved most of the cases.I don't know the reason.