MalLevelexpBoost

//=============================================================================
// Maliki's Level Based Experience Point Boost
// MalLevelexpBoost.js
// version 1.0
//=============================================================================
/*:
 * @plugindesc Version 1.0 Allows devs to implement a slight curve on Exp gain
 * based on actor level.
 * @author Maliki79
 * @help You need two steps to use this plugin:
 * 1: Create an Enemy troop
 * 2: Use a Script Call during turn 0 - 0 to set Enemy "Level" to base curve on.
 *
 * To use this, you first set an enemy troop level. (This plugin will not work
 * with individual enemy levels)  By default, RPG Maker MV does not give enemies
 * levels, so we must set them per troop via a script call.
 *
 * $gameParty.setEnemyLevel(x);
 * with x being a positive integer.
 *
 * After battle, this number will be compared against each actor's level and a bonus
 * will be granted based on the difference.
 * For each level higher the troop is than an actor, 10% exp gain will be added.
 * Conversly, every level below will reduce the gain by 10%.
 * There is no cap to how much it is rasied, but the lowest it currently will go is
 * 10%.
 * (If there is no number set at the start of battle, the troop level will be set to
 * the actor team's average level.)
 *
 * Note that while you technically do not need it, without YF's VictoryAftermath
 * plugin, you won't see the difference in exp gain between actors.
 */

 Game_Party.prototype.averageLevel = function() {
    var level = 0;
    for (var i = 0; i < this.members().length; ++i) {
      var member = this.members()[i];
      if (member) level += member.level;
    }
    level /= this.members().length;
    return level;
};

var MalStartBattle = BattleManager.startBattle;
BattleManager.startBattle = function() {
    MalStartBattle.call(this);
    $gameParty._troupeLevel = Number($gameParty.averageLevel());
};

Game_Party.prototype.setEnemyLevel = function(tLevel) {
    var level = Number(tLevel);
    this._troupeLevel = level;
};

BattleManager.gainExp = function() {
    var exp = this._rewards.exp;
    var diff = 0;
    $gameParty.allMembers().forEach(function(actor) {
        diff = 1 + (($gameParty._troupeLevel - actor._level) * 0.1);
        if (diff < 0.1) diff = 0.1;
        var finalNum = Math.round(exp * diff);
        actor.gainExp(finalNum);
    });
};