experience drops aren't accurate

[83y]

Hi, im trying to make xp drop when a player dies however, when the player dies and the xp drops, the xp drop is accurate in the broadcast, but when I go to pick up the xp orb the amount of xp is different. How do I fix this?

on death:
    if attacker is a player:
        if victim is a player:
            set {_loc} to victim's location
            set {_attackersxp} to attacker's xp
            broadcast "%{_attackersxp}%"
            set {_xp} to (20 + ({_attackersxp} * 1.33 ))
            spawn {_xp} of xp at {_loc}
            broadcast "%{_xp}%"

Im using 1.8.8 paper spigot