engineer told me increasing SNR is a bad thing

I moved to talktalk in november.The router is trying to connect at around 5.5mb download speeds, leaving a SNR of 6db. This is usually fine for a few hours, or usually till the evening, when the SNR begins to drop below 6db and the line loses sync. I have to reboot the router several times, and eventually it connects at around 4.5mb and things go back to normal. But then the stupid thing decides to reconnect at higher speeds by itself then next day, and the process repeats.

I phoned talktalk, and spent hours trying to convince someone that I needed the line capped at around 4.5mb, because its just not stable at above 5mb. I had the same issue with SKY previously and they had capped it to make it stable.

Eventually i talked to someone in talktalk who saw that there were issues with the line, errors from their end also. they arranged for an engineer to come out.

The engineer came this morning, did his tests and then told me that every time he tried to increase the SNR it would skip the 9db profile and go to the 12db profile. this he said was "bad" and caused to many errors and left the line unstable???? He said the 6db profile was a good profile, because it "will never go below 6db and the line will remain stable"??????

I mean the guy had a tablet with lots of tests that he was running , and graphs and results that he clearly needed to interpret. so he must know something about his field, but what the heck is he talking about?

Increasing the SNR to 12db will leave the line MORE unstable or cause MORE errors or less? This is a first for me. When i joined talktalk the profile was 12db, and the line only connected at 2.5mb. It was stable and i requested them to lower the SNR profile to enable a faster connection. Now they are saying that they cant increase the SNR?

Go here:

http://community.talktalk.co.uk/

And post and ask to be put on a 9db profile.

That way when the snr drops it will hopefully stay above 6db and wont disconnect.

You may lose 1-2mb in sync though.

Yes, i could try that now as a last resort. but ive already had the engineers look at the issue over the phone and Ive had an engineer come to my house, and check the exchange. And hes the one that told me all the gobbeldegook . Yet he was unable to move the profile up.