Exp split in groups, when chars are at different levels - what data do we need to figure it out?

[Fuii]

My initial speculation is that there's some sort of average group level that's calculated and then each character's deviation from that average level reduces experience awarded.

That's the TL;DR

XP is affected by:
- mob level
- individual character level
- group size (in XP-range at time of kill)
- average group level (in XP-range at time of kill)
- mob type (normal 100% vs. elite 200%)

Mob base xp = character level * 5 + 45

To that the following modifiers will be applied (additive):

Difficulty mod = +5% per mob level above player level, up to +20%
Group bonus = up to 40% bonus for 5-man
Mob type = +100%

Thus the maximum bonus can be 160% on the base XP.
Resulting in an "effective base xp".

In a group the average group level is used for the difficulty modifier, instead of the individual level.

Example group: 20 / 20 / 20 / 20 / 60 => average is 28

The group is killing an elite monster of level 30, resulting in:


Base XP = 20 * 5 + 45 = 145 XP
Difficulty bonus = 10% (mob 2 level above grp avg) = 14.5 XP
Group bonus = 40% = 58 XP
Mob type bonus= 100% = 145 XP

Total XP = 363
XP for each lvl 20 = 73 (363 / 5)

Let's say one of the 20s is now 21, the rest remains 20 and the 60 boosting.
The lvl 20s will still get 73 XP.

However, the 1 additional level for the 21 char does increase his personal base xp from 145 to 150, thus:
(the average group level remains the same)

Base XP = 21 * 5 + 45 = 150 XP
Difficulty bonus = 10% (mob 2 level above grp avg) = 15 XP
Group bonus = 40% = 60 XP
Mob type bonus= 100% = 150 XP

Giving him the individual base XP of 375, divided by 5 netting 75 XP for the kill of the same mob.


That higher level people are getting more XP than lowbies is simply due to the base XP calculation.
That's Blizzard ways of capping the max XP per mob, regardless of level difference.


I'm actually more interested in the mechanic of pet-tag boosting and why an additional character in your group yields bonus XP, even if he's not in XP range.