Of course there are many international kindergartens with school fee over 4K, some even as high as to around 10K per month. But there are still international kindergartens with all native english speaking teachers still charging less than $4,800 per month, such as
Kowloon Baptist Church Kindergarten http://www.kbck.edu.hk/ ($2,200 per month) [this is a kinder which the principal bothers to spend time to have individual interview with parents of all applicants, with over 30 mins per each kid]
Small World Christian Kindergarten http://www.swck.edu.hk/about ($4,295 per month) [some teachers there even got professional Montessori teaching qualification]
YMCA International Kindergarten in TST ($4,680 per month)
Employing native english speaking teachers does cost a lot but doesn't mean that the school fee must be expensive. The gist is whether the kindergarten is profit-making or not.
Back to the main issue, as a parent, I totally understand the anger and frustration of the parents here. Have you considered the case in their perspective? Your reply in BK is not addressing the concerns of the K2 parents in your school. What's the explanation to change their kids to pm class without getting their prior consent (note: I mean consent, not just inform them)?
For parents planning to go to N1/K1 in LK in the coming year, please think deeply. Today, they can suddenly change the schedule of K2 classes w/o getting parents' consent (no matter whatever reason, to accomodate the N1 or not), no one can guarantee that the same incident will not happen again.