Anybody know the leeching formula for EXP at LHC/LKC or SH?

First, the damage part: the level 160 gets 20,000 for that, nobody else gets anything.

Then, the split by level part. Adding up all the levels: 110+120+130+140+150+160 = 810
110/810 = ~13.6%, so that guy will get 13.6% of 80,000 = 10864
and by the same token, the 120 gets 11851
and so on
160/810 = 19.7%, so the attacker gets 15802 of the 80,000, for a total of 35802.

Now we multiply each by 2.8 to get the party bonus. So the 160 gets 35802 * 2.8 = 100,245 bonus.
The 110 gets 10864 * 2.8 bonus, so 30,419.

The others I leave as an exercise for you.