^ Wont work well. If the player can calculate the when the timer expires, before that, he threw the item out, it wont be leveled up and will never be leveled up again.
Therefore, I suggest u check if the hero still has that item or not. If he has, level up it (like what u show in ur trigger). If he doesnt, add him to a unit group. Whenever the hero acquire that item after being added to the unit group, he will instantly leveled up. After the leveled up, remove him from the unit group.