Comment on BTO payment timeline – Buying via BTO, SBF or Open Booking? All you need to know about the payment timeline by Pang

Hi,

If we are buying a BTO flat of $600K.
We are taking HDB loan and our combined income can only loan up to $400.
15% down payment upon booking a flat e.g $90K
Our question is when do we need to pay the balance cash of $110K ($600K-$400K-$90K) ? upon collection of key or during booking?

Thanks.