The 3 FTTC DLM profiles dont set to fast path or interleaving, they actually all by default an open profile, so sky cannot force interleaving they also cannot force fast path. But the profiles do affect how likely DLM is to take actions to stabilise the line. To do a DLM reset yes an engineer is needed. But my point is a user on the speed profile can have a line with more errors whilst remaining in the fast open profile than a user on the standard profile.
Also the backhaul can mean a noticeable difference as the networks are built differently to each other, so it will affect routing which in turn affects base latency.
Sadly on pro you cannot adjust anything on FTTC by yourself other than toggling the static ip on/off.
