Driver measurements result(Sorry to bother you again)

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Ok so I own an vellmann multimeter that has these specifications(the best I could find around and aford)
Features
Specifications

DC voltage: 200m/2/20/200 /1000V
basic accuracy: ±0.5% (±0.8% for 1000V range)
input impedance: 10Mohm
maximum input: 1000V
AC voltage: 2/20/200/750V
basic accuracy: ±0.8% (±1.2% for 750V range)
input impedance: 10Mohm
frequency range: 40-400Hz
maximum input: 750V
DC current: 200µ/2m/20m/200m/20A
basic accuracy: ±0.8% (±2.0% for 20A range)
overload protection: 0.2A (20A range not protected by fuse)
AC current: 2m/20m/200m/20A
basic accuracy: ±0.8% (±3.0% for 20A range)
overload protection: 0.2A (20A range not protected by fuse)
resistance: 200/2k/20k/200k/2M/20M/200M
basic accuracy: ±0.8% (±1% for 20M range)
overload protection: 250V
I used this method :
http://sound.westhost.com/tsp.htm

So RS is an 8.3 Ohms resistor in series with my driver(Re=3.9ohms).
I got this measurements

For 200Hz Vs is 810 mV
Is=66.393

Fs=23 Hz Vm=266 mV
Im=32.028
Rm=16.97
ro=2.07
Ir=46,127
Vr=382.854
Fsh=29,4Hz
Fsl=17.3Hz
Added mass(I used this method for VAS)
Mass=22g
Fb=19.2Hz

I obtained

Qts=0.720
Vas=674.594 litres

I know that the measurements are not very accurate because of the frequency stability of the multimeter but testing it,it turned out that the error was under 20% untill about 15Hz when it got to about 50%.
Assuming the measurements allmost corect could you check the calculations for me and tell me if you see anything wrong...
The driver is a Senon (Chineese) and is 12" in diameter, magnet 40 Oz and 2" voice coil.
Here is a picture.

Thanks.

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After playing a bit with winisd here is what I found...What would you do?
Please guys I really need some advice and help....
Here is the pic for a box of 500litres using the data I measured...

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VAS seems a bit high...