You appear to have misunderstood what I have said.
What I meant was, if you see the SNRM go up or down, but the DSL remains connected, then it was not the DLM's doing.
Yes I know the DLM can disconnect the DSL to change the target SNRM, but that's not "while the DSL remains connected".
Heyho's graphs showed the SNRM changing, but the connection speed was the same before and after, so I assumed there had been no re-sync, the DSL stayed connected, therefore the changing of the SNRM was not the work of the DLM.