Second-hand housing loans are calculated according to the bank valuation, and the general bank valuation is about 80-85% of your house price. Let's calculate by 85%. The bank valuation of an 8 million house is 6.8 million, and your first loan is 60%, so you can borrow 4.08 million. Your down payment is 800-408+21.6+(10or40) = 423.6 or 453.6.

The down payment ratio is generally above 50%, which is higher than that of new houses.

The new house is loaned at 60% of the transaction price. For example, if the transaction price is 5 million, then you can borrow 3 million.