The maximum social security amount per year is $106,800
(so sayeth ehow, http://www.ehow.com/info_7789422_maximum-security-tax-per-year.html )
Which means whoever came up with the $40 is referencing the -maximum- possible savings, not the typical or average.
$41.07 says the TI calculator.
When people got into such a frenzy about the $5 charge per month for using an ATM 0bama took note and is running with the $40 since that would be an outrage if $5 was a frenzy!