Leveling Party MUST be within the area radius.

If nt wont have the exp shared.

If im not mistaken, lvl 60 char kill, lvl lowered friend will still get the actual exp as per normal, but IF the lvl lowered friend do kill providing you have Grant Exp per KIll ITEM, then you will have extra.

But if u don't kill and let your friend kill, you still will have the normal exp as though as if you kill it.

If your LVL 60 friend have exp grant items, it is not shared among all. Only to the killer.

This is based on my experience helping my friends.

So conclusion if your helping your friend, best just tank, and let him kill if he have the extra grant items.