RTP Allocating from port range 5000 -> 31000

Hi all!

I am a newbee in FreePBX. So i have much questions. Hope you help me.
my system:
Asterisk 1.6.0.1
FreePBX 2.8.1.0

when i change RTP port on etc/asterisk/rtp.conf with below:
rtpstart=10001
rtpend=20000

and then I reload amportal with command:
amportal stop
amportal start

when i make a command “reload” on CLI, i got it “RTP Allocating from port range 5000 -> 31000”.
I don’t known why RTP will give port range: 5000 -> 31000 while i changed with 10001 -> 20000.
Please help me.

Thanks,