SNR Jumping up and down

[#1]

I have just been migrated to 21CN ADSL2 but have had a few problems with my ADSL line for a week or so now.  Before I was on ADSL max and getting an ok speed 2800 compared to LLU which was high about 3800.  I am recently getting big SNR drops for no reason.  Before I was getting a default download SNR of 12db, it then went up to 15db, but now keeps jumping up to 25db and over, then after a while drops back down to 15db or 12db.
What could be causing these eratic SNR jumps, it was fine when it was on LLU.
Could the Route or Filter be at fault.
Wed 16 Sep 2009  17:19:57 Rx-Noise=10.2 Tx-Noise=13 Rx-Sync=2688 Tx-Sync=448
Wed 16 Sep 2009  17:22:34 Rx-Noise=15.4 Tx-Noise=16 Rx-Sync=1856 Tx-Sync=448
Thu 17 Sep 2009  02:24:43 Rx-Noise=13.6 Tx-Noise=15 Rx-Sync=992 Tx-Sync=448
Thu 17 Sep 2009  02:25:03 Rx-Noise=24.4 Tx-Noise=15 Rx-Sync=992 Tx-Sync=448
Thu 17 Sep 2009  21:54:51 Rx-Noise=15.4 Tx-Noise=6.1 Rx-Sync=814 Tx-Sync=739
Thu 17 Sep 2009  21:55:11 Rx-Noise=23.6 Tx-Noise=6.1 Rx-Sync=814 Tx-Sync=739

[#2]

It looks like your profile may have been banded.
Do you see any changes after rebooting today?

[#3]

James,
I rebooted the router this morning and it synced with the below details.
Fri 18 Sep 2009  08:12:11 Rx-Noise=15.3 Tx-Noise=5.9 Rx-Sync=2170 Tx-Sync=611
But then at 9:32 this morning it resynced its self with the bellow:
Fri 18 Sep 2009  09:32:10                Rx-Noise=15.3 Tx-Noise=5.4 Rx-Sync=2170 Tx-Sync=61
Fri 18 Sep 2009  09:32:30 Rx-Noise=0 Tx-Noise=0                     Rx-Sync=0                       Tx-Sync=0
Fri 18 Sep 2009  09:32:51 Rx-Noise=0 Tx-Noise=0                     Rx-Sync=0                     Tx-Sync=0
Fri 18 Sep 2009  09:33:10 Rx-Noise=6.8 Tx-Noise=5.9 Rx-Sync=2592 Tx-Sync=739
Its the first time I have seen a Noise Margin of 6 on the downstream on my line for about 2/3 weeks

[#4]

Looking at the drop in sync, it looks like your line profile was recalculated.

[#5]

My line is still bouncing all over the place at the moment,  the SNR on it seems to get set from anything to 6db to 25db down stream still.  I am also getting 172 addresses a few time 3/4 times now since being migrated on Thursday.
I am also having to restart the router a lot, if it is not for the 172. ip address issue, I am being synced, but just getting no throughput and so am having to restart the router for this.
I have used the same router for about the last 2 years on LLU is was 100% stable with a download rate of between 3400 - 3800.  My line is now bouncing about betwenn 1024 and 2688 and seems to be extreamly unstable.  Is this just the inital 10 days training period and then things will settle down back with decent sync speads or is this all as a result of the ADSL2 trial.  If it is I am not very happy with this, i shouldnt have to reboot my router and as far as I am aware the router should not be resyncing ever 3-4 hours with wild SNR changes.
I understand that this is a trial and there may be some teething problems, but they seem to be very extream teething problems.  Is there anythink that I can do or someone at Plusnet to settle the SNR jumps down and perhaps get my download sync speed back up to mid to late 3000's as thinks are not looking good for BT ADSL or BT 21CN compared to Tiscali LLU that I was on prevously.

[#6]

It's quite possible that it's because of the training period.
I'd suggest giving it the ten days first then see if there is any improvement in stability - if not, we can raise with BT.