The fact of the matter is, coming back to Chestnut's original thread question is..
Yes, the government will reduce ABSD, for sure, if property market starts to weaken rapidly. In fact, they will do all sorts of things in a crisis scenario to prevent property valuation from coming down too low, too fast.
Take the example of what the FED and the US government did during the US financial crisis (08-09). They nationalized Fannie Mae + Freddie Mac, used the FED to intervene in MBS (mortgage back securities), allowed troubled banks to sell their depressed loans to govenrment agencies as collateral.
In the worst case scenario, if property valuations > -50%, mark my word - they may even nationalize companies like capitaland, etc because these are flagship economic entities of Singapore. But will we go there, probably not.
With regards to ABSD -> keep in mind, this is a measure undertaken by the government in a very delayed manner after prices have gone up.
I will think that reduction of ABSD will also happen in a delayed manner.
Question is, how to time this? Impossible. You probably have better luck timing in buying a stock then to time a government measure.
In M'sia, they did the same thing towards foreigners (quota). During the late 1990s when everyone was rushing into M'sia they reduced the quota drastically. But did they start increasing the quota when prices have bottomed? No.
What i am trying to say is, your expectation of ABSD timing is irrelevant. You are much better off in timing your entry price. Whether the government is on your side at that time, no one can predict.