Hey
You got me thinking so chased up the info from our fleet to confirm latest Mod status.
OK it goes like this....Early 767...did not have any load shedding.
Then next mod was if both BTBs closed (one power source) aircraft load shed but NO load shed if 2 power supplies (normal config)
Latest Mod ( I do stand corrected)
But now with incorp. of SB 28-0025 Rev 1,
Load shedding happens when Jettison selected whether with 1 or 2 power supplies
Items IFE and PES are shed plus #3 L/ R cockpit window
Load shedding is there to prevent possible source overloads?
Equipment cooling fans are not load shed.
Hope this helps and ends the discussion