Developer is already out of the picture once the property is completed and handover to customer.
The financing part is only between the bank and buyer (prop owner).

Prepayment comes in many form but let me explain in flexi-home loan for better understanding:
Let say you have outstanding loan balance (OS) of Rm100k.
You have Rm20k cash you wanna pre-pay for the loan.
So your OS becomes Rm80k. The day Rm20k was credit into your loan account, the interest calculation is base on the new OS of Rm80k.

The next day you wish to take out Rm5k from the pre-pay of Rm20. Your new OS is now Rm85k. And so the interest is calculated on Rm85k.

Property loan interest calculation is on DAILY rest. Like FD is on ANNUAL rest. Compounded DAILY or ANNUALLY. Can you imagine (hypothetical) FD is 3% on DAILY rest. Your money + interest is compounded DAILY. You make a lot of money. 

But banks wanna make money mah .... so here is the real scenario
LOAN: Rm100k. Interest: 4% per annum (Compounded DAILY). 12 days to make Rm4,074.
FD: Rm100k. Interest: 4% per annum    (Compounded ANNUALLY). 12 months to make Rm4,000

Understanding this concept of bank calculation, don't you think PRE-PAYMENT is a better option?
Many will look at interest per annum only but with TIME factor, banks will always beat you to the game.