So this is how it worked with us. When we went in, we handed all our documents to the guy at the reception window. They asked my wife (PA) if she wants to do the interview in English or Urdu. She picked English but other people who picked Urdu were provided with an interpreter. Then we waited for about 2 hours (we got there early). When it was out turn, my wife was called in. She was interviewed for about 45 minutes. Then she came out and I was asked to go in. I was there for about 20 minutes. The officer had already reviewed all our documents before even calling us in. Hard to say how much she looked at but she did ask us some questions about it so she must have at least skimmed through the chat. We had also put sticky notes on stuff to organize it.
And yeah I wasn't asked to be at the interview, but they did say if I'm not in Pakistan, I should be available on the phone. I didn't want to leave anything to chance so I flew back for a week.