the current share price of $1.63 is too close to the entitlement...

the current share price of $1.63 is too close to the entitlement offer price of $1.58 which could mean a lot of shareholders will not bother taking up the shares that they are entitled. Also, taking into account that FOR NAV is now at $1.53 and is below the entitlement offer price. So the likely result is only half of the shares are taken up. Those shares not taken up is called shortfall.
Now you can apply more than you are entitled to in this FOR offer. And the likelihood is FOR will grab it as quickly as they could!