Does anyone have any idea how instance XP is calculated? It's definitely different, because killing gray elites in an instance with a 60 still gives meaningful XP to lowbies but killing gray elites in the world does not.

There is also the matter of why having 4 lowbies + 1 60 gives more XP than 1 lowbie + 1 60. There is the obvious group modifier 1.166x for 3, 1.3x for 4, 1.4x for 5, but that would only increase the XP summed across the party, the XP for each individual player should be overall diminished but it is not.

With base mob XP, assumed corrected for level imbalances = MXP, 1 lowbie + 1 60 should be 0.5*MXP xp for the lowbie. With 3, it should be .39(MXP), 5 would be .28(MXP).

We would expect to see per-mob XP go down for each additional lowbie. In practice, we observe the per-mob XP go UP for each individual lowbie that joins the group.

At first I speculated there may be some level averaging going on, and I see other people mention that, but I don't believe that to be the case as iirc adding an additional 60 (2 60s, 3 lowbies) doesn't diminish the XP as would happen if there were level averaging at play (I need to double check this)