Do you still have DSLstats running.. if so a capture of the period 6pm to 9.30pm would be worth having a closer look at.
DSLstats is good for monitoring live and 2hr snapshots sometimes show things in a bit more clarity. HG612_modem_stats is great for graphing and some more detailed info. I run both as they each have their own plus points.
May be a bit late now, but you say you were out at that time... is it possible that someone rang at that particular time?. The sharp spikes you see at about 6 & 9 look very similar to what I saw with my recent line fault when ever the phone rang.
Did you ever try as I suggested earlier to observe the SNRm when the phone rang. You can use BTs ringback service test on 17070. Whilst there may as well try the quiet line test to see if you can hear any noise.
My line fault mostly only affected the upstream, there was some signs on the down, but nowhere near like on the up. I have surplus SNRm though and it was only when things were pretty dire on the upstream that Id see it reflected in the down too.
I had what the BT engineer called a 'double whammy fault'. Some of the issues - such as random upstream SNRm fluctuations - were resolved after replacing a faulty NTE, but others such as the SNRm spikes and noisy voice calls remained until a dside swap.
BE - would be good to see if PN can pull the crosstalk test results for you to give an answer there for sure. They seem to have the data available to them!
It looks like perhaps this may be a new test? Im sure that if it was available earlier then either me or BE would have seen them.
It certainly cant harm asking.. Although Im not sure if it would discover FEXT.. which is detected and measured from the EUsite. I suppose it depends on how advanced the tests are.. and if a signal is reflected back down the line?