I was taught as a very junior student of flying that you do not go even a pencil line thickness outside the W & B envelope in normal operations. I was told to treat this as non negotiable.
A sound practice for the line pilot. This presumes, of course, that the loading system is kosher.
As a side note, there is
a thread on Bob Tait's website relating to trimsheet loading systems which may be of value to the Standards side of the discussion in the present thread.
It seems that there might be a few examples out there in the Industry which don't quite pass muster.