Frequent internet drops and T3/T4 timeouts - tech says all is well!

Hi there! 

Hoping someone can advise me on how to proceed. I've been having internet connection issues for several weeks, often worse on weekends and in evening but overall quite unpredictable and variable in timing. Some days I cannot stream a movie without the spinning circle and/or "you are not connected to the internet" appearing every few mins. My son who games says the internet is often glitchy and notices it more than when watching TV. I spent 2 hrs with 2 different support techs who said they were 100% sure they fixed the problem and everything looked great at their end but really they made no difference at all. Finally I was able to convince them to send a tech out who when I showed them some modem logs said he had no idea what they meant. He measured the downstream power and said it was too high (about 10dBmV) saying it could overwhelm the modem and even damage it and just installed a splitter/attenuator to reduce the downstream power by 5dBmV. He said the signal was great and if there were still problems then my modem (Motorola MB8611) must be bad. The problem as I suspected continued after the tech visit.

I have read that T3 and T4 timeouts are rarely if ever due to the modem and more likely something to do with excessive noise from the node or ISP plant. I also noticed there are lots of corrected and uncorrected errors which again seem to point to line noise issues from my research.

Please let me know how I should proceed to get this sorted. Thanks in advance!

Here is the modem log from the day after the tech visit. Overall a pretty good 24hrs actually. It's been much worse.

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Here is the connection info after several days of restarting the modem: