Variable load and js0987,
I have worked with the 92 at a few companies, one place we always bugged and switched. The other company didn't, which is why you are involved in this topic.
The bug is set on the DG for reference, (very good idea for a floating rig or any for that matter) then you watch it to see if it moves off when you switch to DG.
It is recomended by many flight depts. and A/C manufactures. To avoid any magnetic variations from large metal obstacles.
Have you not seen this before?
Though by all means do as you like, feel free never to question the merits of a checklist.... its all up to you.