That is because you are assuming the $1M loan interest rate is 1.5% lah!
Now SIBOR + 0.9 already almost 2.0%!
At the rate SIBOR is rising, soon mortgage loan interest rate will hit 3.5%!
At that rate, I rather sell my bonds (those earning 2.5-3.5% range of coupons) to redeem all my property loans!