I was thinking about the comment from @fablab_elpaso in another thread:
You also lose power as the beam passes through the air from one end of the bed to the other. So, maximal power is usually at top left of the work area (where beam path is shortest) and drops off significantly at bottom right (where beam path is longest).
Is this variance likely to be of an amount that will make a visible difference in a piece of work, and if so, can it be automatically taken into account by the Glowforge software when figuring the tool paths?
And on a similar note, one would think that as output power may decrease with tube life, some sort of calibration would be required to get consistent results between pieces engraved on a new machine vs. pieces engraved on an older one.