All right for some, then?
After too many resets one day late last summer, I fought tooth-and-nail with Demon to get mine reset from 15dB to 9dB and, eventually they did, last September or thereabouts. 48 hours later (possibly to the minute, curiously), it retrained itself at 15dB again and has stayed there ever since.
I now tweak it using the CLI of the DG834GT, which seems to allow up to -6dB relative to target. Although it's happy tweaked to -6 (9dB at sync), I've settled on a -3dB tweak (12dB at sync) for extra stability, and to ensure that if DLM did reduce the target, I'd still sync at 9 which I know to be stable (I'm not so sure 6 would be stable). I live in hope, week on week, and month on month, that one day I'll check and find it's resynced at 9, but it just doesn't seem to happen.
On theory I have is that, because my line is so much improved (just by cutting the bell-wire) since the 10-day period, DLM can increase the target without me getting anyware close to my FTR. And just maybe, because I'm syncing at a long way above my recorded FTR, DLM is less inclined to give back my margin.