No one, apart from those in BT, knows what the parameters are to switch from a 6dB to 3dB profile or back. It could look at up time, error rates, total errors, SNR variation over 24/48 hours, how close you are to your service speed (80/55/40/15), have you have 3dB before and DLM reverted you to 6dB and probably a combination of factors.
It will be a case of wait and see.
M H C
taurus excreta cerebrum vincit