Medical aid deduction - challenge SARS

A simple calculation for any one?

Year: 2012
Taxable Income R118 472
Medical aid contribution R 38 772 – two persons for the whole year.
Portion self-paid R784.

Under 65
No Disabilities

SARS result = R31 967
Me = R 30 670

My calculation:

Caped amount: 720 X 12 X 2 = R17 280 (a)

Portion over Cap = R 21 492
Self-Paid = R 784
Thus Amount subject to 7.5% of taxable income = 21 492 + 784 - (7.5% * 118 472) = 13 390 (b)

Deduction = R 30 670 (a)+(b)

Who is the dummy ?