Current Line Speed Confusion

[#1]

Hi to all,
I am hoping someone here will be able to help me.
My current line speed is recorded by PlusNet as 13000 and I am on Profile Nr 6 which I assume it means something to PlusNet and BT.
I do not have my router stats and noise margins at hand, but I know I am very close to my exchange and when I previously went to kitz at http://www.kitz.co.uk/adsl/max_speed_calc.php and input attenuation etc., the site returned the maximum possible results, i.e. 24Mbps.
Don't get me wrong, I am getting some brilliant speeds particularly since I upgraded to Pro. Even on peak times my speeds are fast enough.
However, I might be wrong but is BT deliberately 'managing expectations' by not allowing my line to max out?
Any help will be appreciated.
I can post the actual margins when I get home later on today.
Michael

[#2]

We'll need the stats reported by your router and the results from a BT speed test please.

[#3]

Hi there, my router stats are as follows:
Data Rate(Kbps): Downstream 15323 Upstream 1057
Noise Margin (dB): Downstream 16.7 Upstream 6.2
Output Power (dBm): Downstream 20.3 Upstream 12.4
Attenuation(dB): Downstream 12.0 Upstream 4.2
Will post on the BT Speed Test as soon as possible
Attached are the router stats and the result from http://www.kitz.co.uk/adsl/max_speed_calc.php
Thanks
Michael

[#4]

And these are the BT Tester results which are not any more clear to me!
"Download speedachieved during the test was - 12728 Kbps
For your connection, the acceptable range of speedsis 1000-99999 Kbps.
Additional Information:
Your DSL Connection Rate :15320 Kbps(DOWN-STREAM), 1056 Kbps(UP-STREAM)
IP Profile for your line is - 13000 Kbps
The throughput of Best Efforts (BE) classes achieved during the test is - 10.08:26.38:63.54 (SBE:NBE:PBE)
These figures represent the ratio while sententiously passing Sub BE, Normal BE and Priority BE marked traffic.
The results of this test will vary depending on the way your ISP has decided to use these traffic classes."
Any help will be appreciated.
Thanks guys
Michael