Here's what I mean. You have enough Learning to gain 10% extra XP. This bonus means that by the time you would normally have accumulated enough XP to reach level 50, say, without Learning, then with it you would be at level 55 ? Surely that's a 10% gain ?

Well, no, it doesn't work that way, because the increased XP to reach each new level works out as a *percentage* of that needed for the previous level. So in fact, any level of Learning doesn't compound levels as you go up - it gives you a *constant* gain in levels as you go up.

To clarify - if you have enough learning to keep you one single level higher at level 20, then when you reach level 100 you will still be exactly one level in advance of where you'd be otherwise.