Question for Yew Chung parents

I learnt from Yew Chung's website that the tuition fee is around $120,000 to $130,000 per year which seems affordable to many. And there is no debenture arrangements. However, friends told me that international schools always have different reasons to charge parents e.g. school renovation contributions etc. One would have a clearer idea how much you will actually be paying for a school that asks for debenture than for one that doesn't.