Yes you are absolutely right, the commercial awareness questions, knowledge about the service lines (especially the one you are applying) and how could PwC benefit their clients would be covered somehow in the interview. The approach my partner used for assessing this kind of questions was asking them throughout the whole interview, depending how I responded the questions. For example, I was talking about my summer internship with one of the big bank, who is a audit client of PwC. After I explained what I have learned from that summer internship, she then quickly asked me a commercial awareness question specific to that bank and how PwC could benefit this client.
It would be helpful to go back to your application form and go through what you have put down and make some more research and preparation into it.
Hope this help.