WiMAX throughput calculations

Hi all,

I am trying to calculate the PHY data rate of WiMAX (OFDMA-IEEE
208.16e) for different BW values (3.5,7,8.75,10,and 20MHz).
The WiMAX forum document (Mobile WiMAX – Part I: A Technical Overview
and Performance Evaluation) gives these rates for DL PUSC for 5MHz,
and 10 MHz..

My calculations don't match with theirs !
Here you are how I proceed:

The PHY DATA rate = The number of Used Data Subcarriers * (Number of
bits /subcarrier) / Ts

where :
-The number of Used Data Subcarriers = 360 for DL PUSC (given in the
standard)
- Number of bits /subcarrier depends on the MCS used ( i.e. 2 *0.5 for
QPSK-1/2)
-Ts : is the OFDM symbol duration (= Tb + Tg)
-Tb = 1/delta_f
-Tg = Tb/8
-delta_f depends on the FFT size.
all these relations are given in the standard.

Am I proceeding in the right way ??
I'm also wondering why the Frame_Duration (i.e. 5ms is not used in my
calculations) !?
Does that mean the throughput doesn't depend on the Frame_Duration ?!
(a bit strange)
Any comments would be really appreciated..

Thanks
Best Regards
Hany Kamal