Why do Plusnet apply own line speed limits?

[#1]

Yet again I am stuck with very slow speed because the Plusnet line limit has not been updated after BT IP profile returned to usual value. This having to put in a support notice to get this updated is a real pain. If ultimately the BT IP profile limits speed why add another layer of complexity which seems rather unreliable?

[#2]

Hi there,
There is a good reason for this, it's to ensure our traffic prioritisation system work's correctly. It has been a topic of discussion of late so let me link you to the relevant thread which includes a detailed explanation:
http://community.plus.net/forum/index.php/topic,97407.msg836049.html#msg836049

[#3]

@datsme, additionally,
I have updated your Plusnet profile to 5500kbps to match your IP profile.  This will be live within the next 30 minutes.  With our current system your Plusnet profile should update within 12 to 24 hours following a change of IP profile.  Unfortunately there can be a short period of overlap when the IP profile updates BT side and our profile has not yet moved as our network only adjusts once we receive a report from BT confirming the IP profile change.
I can see that your line is enabled for DLM quantisation which means your IP profile will update immediately once your sync rate changes.  Our developers are currently working on a solution that will mean our profile updates in a similar fashion to resolve this issue in full.
If you have any further issues please do not hesitate to contact us.