If you intend to purchase the property in cash but you want to enjoy the DIBS benefits from the developer, why not you proceed to apply for a bank loan? I believe most DIBS project offers free legal/stamping fees, just find a bank with only has 2 years lock-in period which is also the same duration of the property development.

In this case you can enjoy all the DIBS benefits and when the property is ready, you just settle the bank loan immediately. You do not need to pledge your money which locks your flexibility of investing that money during the DIBS period.

For TS, the property is a under-con project and is DIBS in nature. So the developer is servicing the interest for you during the development period. If you pay in cash, the developer is not going to rebate you the amount of interest that the developer supposed to pay to the bank during the construction period.

So in short, why do you want to help the developer save the money by paying them straightaway even though unit is not ready. You can use that cash to do other investment during that construction period which may bring you better returns to fund your renovation in the future.