I'm with EE on a recently connected ADSL line.
The counts for Interleaved Path FEC Correction on the router are 33205 (far end) and 4329 (near end) after being connected for just over 2 hours.
I had the downstream noise margin reset to 6dB at that time.
Mostly the connection works well apart for a VPN connection using IPSEC which drops 50% of packets when pinging servers on the far side.
I can ping the VPN ip address with no packet loss.
So I'm wondering if the "Interleaved Path FEC Correction" is a cause for concern.
All the other error counts are very low (0, 1 or 2).