[swinog] Minimal S/N margin on Swisscom BBCS VDSL loops

Does some have any guidance as to how much S/N margin Swisscom requires for their BBCS VDSL loops. I have a case where the S/N margin in 22dB on the downstream and it surprises me the line doesn't train at a higher rate (current rate is 13264kbps).

I understand that during the initial setup phase the modem is probed more or less every 24 hours but doesn't seem to update if the line characteristics evolve over time.

If someone can shed some light or provide me with a contact within Swisscom that actually knows the story behind this I would appreciate it.

Thanks Thomas