actually, not totally true also... eg, if you type "upper paya lebar road", it will show the results in a popup. eg choose "terrace house" and it will show the recent transactions with the unit number when you scroll down... then again, maybe this is a recent enhancement to their system.
U r right, it should only be used as a rough guide only.... different house, size, facing, conditions, buyers, sellers will all affect the price...
this is a really really good and important advice, else one may lose the 1% if he/she cannot get the needed bank loan...