Your noise margin was quite (not massively) flappy and up and down. It's probably just the router, you often see this on NETGEAR routers? Were you using one of them?
One of my lines never varied between between 0.1db whereas another could change +-4db.
Looking at the line with a complete flat SNR is normal on plenty of lines. It probably goes down a little overnight.
It just means your line has more noise / your router is reporting more.
Edited by ukhardy07 (Wed 24-Apr-13 05:18:25)