All N class kids were required to attend interview for K1 last November. However, I have never come across any N class kids who have not been offered a K1 place so far.
That sounds make sense as I am sure most of other famous kindergardens also do not require their N1 students to interview in K1 or above. Most likely the N1 students will all be automatically accepted to the upper grades.
What is the reason for requiring N1 students to interview for their K1 class then if they are all supposed to be accepted? Just curious.
By the way, there is a pg in Jul in Think specially offerred to the coming N1 students. If you are interested, you can check with the school.