The two players are within the acceptable 15 level limit Dofus Kamas in game
Say you have a level 50 and a level 35 player. The level 35 players are getting Dofus Kamas xp faster then he normally would in a solo party or any other party. The two players are within the acceptable 15 level limit.
Now the Level 50 player can kill a level 55 monster that is impossible for the level 35 to kill by himself. So normally, the lower level person will be more points then anything he could kill. The kills go faster to as the level 35 player is adding his help too. Second Method of Power Leveling:
METHOD 1 - Basically, in a 2 or 3 man party, they will coordinate on the killing order. For example, in a 2 man party, they both will hit the monster.
The 2 man party may be when both are outside the 15 level cap. But, just before the monster is killed the other people will teleport back to town just before the monster is killed. The other person will kill the monster and REAP all the experience points.
So if the mob gives that person 50k xp, then with the xp scroll, it will be 75k. Then the xp booster multiplies this by 4 and 75k times 4 is 300k. But as you will find they have a level cap.