They are not live at the outset of a new connection, new connections have interleaving applied, then after a few days/weeks g.inp normally kicks in, then if not at full sync and the line can support it the target SNR is gradually dropped from 6 to 3 in stages of 1dB so long as the line can support it and is below the maximum package speed.
ECI cabinets don't support g.inp or dB X, luckily for you they stopped installing ECI years ago and now only install Huawei cabinets.
There's not much you can do to control it, you can force a lower sync, but others know far more about that than I do.