my son said most of the time for reading, then see teacher and being asked a few question only. but i heard some classmates was asked a lot of difficult question, quite different from what my son told me. i guess (just my guess) different students have different format, depending on their first interview performance.
My daughter now is a P1 student. She did take 2nd interview in SFA last year. She told me that the 2nd interview was the form of written and the questions were difficult. Parents were not reuqired to be interviewed.