2006/2007
Annual Income $128,000
Less: MPF ( $6,400)
Assessable income $121,600
Less : donation ($13,500)
Net assessable income $108,100
Less:
Basic allowance ($100,000)
Dependent parents ( $30,000)
Dependent brother ($30,000)
Assesable income NIL
I think you should refer your salaries tax calculation at the back of your demand note and find out the reason of the difference.