What might be going on

[#1]

A week ago I had an Up to 8Mb/s connection that delivered a regular connect at 8128, throughput up to about 7500 kb/s and hardly ever dipped.
I was on an old and expensive package so I upgraded it to up to Premium, largely for a little bit of priority and a high limit of traffic. Like several other got adsl over 21CN, eventually I get a connection at 15Mb/s and throughput of about1700kb/s.
Yesterday morning there were a lot of line drops (every minute or so) and I think some work was going on at the exchange, this has dropped my IP profile from 12M to 10M, this does not worry me because I know it will rise again with stability but why would the throughput be so low?
Support questions re speed all focussed on link speed not throughput.
BT speed tester says
Download speed achieved during the test was - 1655 Kbps
For your connection, the acceptable range of speeds is 1000-99999 Kbps.
Additional Information:
Your DSL Connection Rate :14672 Kbps(DOWN-STREAM), 448 Kbps(UP-STREAM)
IP Profile for your line is - 10000 Kbps
The throughput of Best Efforts (BE) classes achieved during the test is - 21.51:24.83:53.66 (SBE:NBE:PBE)
These figures represent the ratio while sententiously passing Sub BE, Normal BE and Priority BE marked traffic.
I have done this three times as requested in the response to my ticket 32449275
Router stats latest show
Link Information

Uptime: 0 days, 9:38:16
DSL Type: G.992.5 annex A
Bandwidth (Up/Down) [kbps/kbps]: 448 / 12,967
Data Transferred (Sent/Received) [kB/kB]: 0.00 / 19.00
Output Power (Up/Down) [dBm]: 11.5 / 21.0
Line Attenuation (Up/Down) [dB]: 10.0 / 21.5
SN Margin (Up/Down) [dB]: 22.0 / 8.0
Vendor ID (Local/Remote): TMMB / TSTC
Loss of Framing (Local/Remote): 11 / 0
Loss of Signal (Local/Remote): 1 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): 0
Error Seconds (Local/Remote): 15 / 0
FEC Errors (Up/Down): 326 / 37,954,714
CRC Errors (Up/Down): 326 / 37,942
HEC Errors (Up/Down): 1,367 / 31,845
Can anyone please explain what might be wrong, exchange is Christchurch, which shows ok for capacity
Thanks in advance, George

[#2]

The BT speedtester frequently gives nonsense figures for actual throughput, though the IP profile figure is generally correct. Try Plusnet's own speed tester for a more accurate throughput figure (Control Panel, Connection Settings, Speed Tester).
Also, check Plusnet's record of your IP profile (Control Panel, Connection Settings, High-speed Broadband). The line to look for is called something like 'Current line speed'. When the BT profile changes, there's a lag until the Plusnet profile changes - can be up to a day in my experience, though it's supposed to be shorter. Occasionally the Plusnet profile gets stuck, in which case there's a thread here (Plusnet profiles that are stuck) where you can ask for it to be nudged into line with that of BT.
Graham

[#3]

Graham,
Thank you very much for the reply.
On this occasion the BT tester is not lying, that is the speed I am getting for download, and also on other testers.
The checking settings is so obvious, and it is set to 2Mb/s, why do I have to talk to support, write a ticket, fill out a long questionnaire when the answer is so obvious, have added this data to the ticket.
Thanks again, George

[#4]

Hi there,
I've upped your profile to 10000, and fixed a system problem which meant we weren't receiving and processing updates correctly for your line. This means that if your profile does increase again, as it should, it will automatically increase your profile on our system.

[#5]

Just to add, you may need to disconnect and reconnect to get the new profile I've just assigned.

[#6]

Thanks Mand, that has fixed it and I did have to reconnect.
George

[#7]

Excellent, glad to hear it.