Unusual SNR activity with Billion 7800n

[#1]

I recently had a bad phone line problem, subsequently resolved by PN, which caused disconnects. Had  2 engineer visits and the last visit showed that my phone connection at the pole was corroded. Now all better except for one thing.
Ever since the phone problem started i was seeing strange Routerstats graphs showing SNR plunges down to 1-2dB from e.g. 6dB. They do not result in any disconnect at all but this had never happened before in 9 months of using Routerstats Lite with my Billion 7800n. I will attach a pic of what i am talking about (Attachment 2). A yellow triangle appears on Routerstats which indicates "error connecring to router". The "Help" page of routerstats describes this in attachment 1 below.
I have samples which show these "drops" in a session. (attachement 3)
I am trying to determine the cause and need assistance in determining if it is the router or routerstats software that is "erroring".
Can anyone help?

[#2]

I've found Routerstats more prone to these sort of internal glitches than its simpler partner Routerstatslite
I found this by running them both at the same time - and discovered RSlite not recording RS's glitches
This does depend on whether your router will accept more than one single connection to its monitor channel eg through telnet at once to enable both to run at the same time.
I think RSlite always uses telnet wheras RS can possibly either/both use the Http page or telnet depending on the router's chip and the GUI login interface type.
Be also aware that if you are using the web heavily at the time a glitch may be simply because the router has better things to process than a stats request.
So there may be three things here
1 A Routerstats error
2. A Router too busy to bother error
3. A real glitch on the line

[#3]

Does the 7800n use a Broadcom chip? If it does you may want to look at DSLStats
http://dslstats.plainroad.me.uk
The program is a child of  a member of the Kitz forum.