There is no stopping buyer mark up to any price level. Banks cannot question buyer's judgement on the property purchase price. Is a willing buyer seller negotiation.

The bank's business is to provide loan based on their own judgement as provided by a formal valuation report. If the report stated is 500k, then is 500k or any other price

Similarly, a borrower cannot question the bank's judgement on the property price.

In a marked-up transaction, buyer normally will have to bear the 'extra' cost incurred by seller, if any .... legal fees and rpgt.

In addition, for buyer,  the legal fees for SnP and Loan Agreement plus mot and stamp duty are higher base on the amount as stated in the documents.