Below is the breakdown of the Normal Progressive Payment Scheme.

For EC, there is another option of the Payment Schedule called Deffered Payment Scheme.

In this case, after the 20% downpayment is done, the purchaser only start the monthly installment payment after TOP. If you currently own a HDB Flat, you have to dispose it before TOP or paid up the outstanding loan, if any, and dispose the flat within 6 months after TOP for the purpose of getting an 80% loan. A banker will be arranged to explain the details beforehand.

Usually, the purchase price will be slightly higher (eg. 3% more) than the Normal Progressive Payment Scheme.

Read more on Affordability of an EC here