Most of the market price you found in brickz are likely from marked-up selling price to get higher loans from banks to offset the downpayment. For example, the owner wanna sell you 380k, but you markup the loan for 420k, so the bank will give you 378k (90% of the the markup selling price). Thus, the data in the brickz will follow the 420k, although the actual selling price is 380k.

To get better indication of how much you should sell the house, look at similar listing at mudah or iproperty.