EDIT:
In the skillhandler.java you'll see something like this:
Code:
public static final int AGILITY_XP = Config.SKILLING_XP;
public static final int PRAYER_XP = Config.SKILLING_XP;
public static final int MINING_XP = Config.SKILLING_XP;
public static final int COOKING_XP = Config.SKILLING_XP;
public static final int RUNECRAFTING_XP = Config.SKILLING_XP;
public static final int WOODCUTTING_XP = Config.SKILLING_XP;
public static final int THIEVING_XP = Config.SKILLING_XP;
public static final int HERBLORE_XP = Config.SKILLING_XP;
public static final int FISHING_XP = Config.SKILLING_XP;
public static final int FLETCHING_XP = Config.SKILLING_XP;
public static final int FIREMAKING_XP = Config.SKILLING_XP;
and that config.skillxp is in the config.java which is set to 20:
Code:
public static final int SKILLING_XP = 20;
So I guess you have to change the 20 to 5