Perhaps with only being able to link to the thread, you missed the stats in that particular thread which is what I was trying to show. All the stuff that happened afterwards was whilst trying to get the original problem sorted. I went through numerous 'stuck bRAS' problems during that period. The router reporting 8128, and the DLM another figure, didnt occur until later on
If you look closely at the first post stats, you will see I was experiencing the low Output power which is what you are displaying now:-
These were the stats taken from my router after the power outage.
Statistics Downstream Upstream
Line Rate 736 576
Noise Margin 6.8 dB 6.0 dB
Line Attenuation 7.0 dB 7.0 dB
Output Power 11.9 dBm 13.1 dBm
Someone looking at those stats without noticing the power output would think that line is syncing as fast as it possibly can because there is no spare SNRM above 6dB.
It seems that somehow the DLM was able to throttle back the power to 11.9 dBm... meaning that I didnt have any surplus SNRM at all. (default is 6dB)
For comparison, these are some stats showing what the line was usually like
Notice full sync speed, normal tx power in the region of 18dBm, and surplus SNRM over the default 6dB.
Re the sky thread, Sky uses a totally different (new) DLM system. Im not aware that BT 20CN uses ASSIA for powercut back to control DLM.
What is beyond doubt though is that
very short lines do and always have suffered badly when it comes to stuck profiles and odd things happening with the BT 20CN DLM system. Its the reason why I got off it asap and was glad to go LLU adsl2+ (about 2 weeks after that thread).
For some reason, something is holding back your output power, which is why your sync speed is now so low. The fact that there is no surplus SNRM doesnt hold relevance - nor follow the 'normal' rules - in your particular case.
Your line needs a total reset.