Expected: Merc boosts exp gained during leveling by increasing the exp gained on each kill

Actual: Merc boosts exp gained ONLY WHEN IT GETS KILLING BLOW.

Human Settler dying to level 27 character + silver construct:

Construct getting killing blow:

wilderness <65%hp 77%m 18%mv 7692tnl (29.11%) 2 AM> Your horns miss a human settler.
Your goring horns misses a human settler.
You dodge a human settler's charge.
A human settler's charge bounces harmlessly off of your stony hide.
A shining silver construct's punch devastates a human settler!
A shining silver construct's punch EVISCERATES a human settler!
A human settler is DEAD!!
You receive 432 experience points (40% bonus).


wilderness <27%hp 55%m 97%mv 6946tnl (35.98%) 3 PM>
A meandering elf's charge injures you.
A meandering elf's charge wounds you.
You sure are BLEEDING!
A shining silver construct's punch MUTILATES a meandering elf!
A meandering elf is DEAD!!
You receive 579 experience points (40% bonus).
A meandering elf's head is shattered, and his brains splash all over you.

Player getting killing blow:

wilderness <31%hp 66%m 20%mv 7260tnl (33.09%) 4 AM> gore

A human settler's charge wounds you.
A human settler's charge bounces harmlessly off of your stony hide.
A shining silver construct's punch misses a human settler.
A shining silver construct's punch misses a human settler.
Your gore DISMEMBERS a human settler!
A human settler is DEAD!!
You receive 152 experience points (40% bonus).
A human settler's feet are sliced from his dead body.
You can't pick anything up.
The gods give you 13 copper coins for your sacrifice of the corpse of a human settler.
No one is around to take coins from you!

wilderness <73%hp 61%m 100%mv 7098tnl (34.58%) 2 PM>
A meandering elf's charge wounds you.
A meandering elf's charge wounds you.
Your gore DISMEMBERS a meandering elf!
A meandering elf is DEAD!!
You receive 152 experience points (40% bonus).
A meandering elf splatters blood on your armor.
You can't pick anything up.
The gods give you 13 copper coins for your sacrifice of the corpse of a meandering elf.
No one is around to take coins from you!



Let me know if you want the full log.

There are NPC mercenaries (in Galadon) that can group the way a PC can, and experience gained mimics that of player groups.

The construct is not one of those NPCs.

NPC mercs have always behaved the way you describe above.