WBC DLM dropped your sync-time margin to 3dB?
I don't have any previous figures to compare with, but from my router's ADSL status parameters page:
SNR Margin(Upstream) 23.6
SNR Margin(Downstream) 2.7
Line Attenuation(Upstream) 20.9
Line Attenuation(Downstream) 42.5
Are you referring to the SNR Margin (downstream)?