I can confirm the easy level up skill IS working. However, if you have no to little skill in whatever your leveling I believe the trainer adds too much exp. I have had several skills at level 0 max out, and stay stuck there with the option on. So here is how you fix it:
Simply skill up the skill a little first with the option OFF, past level 5 or so, then every skill up will be instant after that when you turn it on.
Hope that helps!