It may have already been interleaved by DLM as I pushed my luck in the first week or so, experimenting with the effects of different router modem locations and modem leads, and how a shielded lead performed vs unshielded, etc. That involved a number of manual restarts, which may have got noticed by DLM. I doubt whether I exceeded 4 restarts in any hour, or 6 in any day, something like that order.
I thought at the time I had got away with it but in the absence of hard stats, can't be sure. Nor can I be sure whether the ping started off at a lower value prior to that early experimentation - just that I think it has been 21mS-ish ever since and still is, despite the DS reduction.
The ZEN portal includes a chart named 'Service Profile data' that used to list DLM/BRAS activities for 20 cn. I know it used to work because it still shows a DLM SNRM adjustment that I know to be accurate, from earlier in the year. I am not expecting that part of the portal to function for FTTC and indeed, there has been nothing new shown since my switch to FTTC, from which I draw no conclusions.