OK, I admit it - I got a bit greedy and decided to experiment with power-leveling myself as a shrouded level 5 critter, using stacks of potions and working the fields of Qeynos Hills. I killed LOADS of rats that conned yellow to me, and each time it said I was getting experience. However, when I went back to "normal" form, it did not show any change in my XP levels under either AA or regular XP. So, that little experiment did not work.
But this started me thinking - how does XP work while shrouded? Do you simply not get any when you play toons that are lower level? Or, does the XP only kick in when you are grouped (or grouped with people who actually ARE that lower level)? I considered that perhaps SOE made this the case to prevent people from doing what I had tried: Soloing lowbie mobs who die easy.
I am still a bit concerned because if you don't get XP while shrouded at all, I'm not sure I would want to do that. I realize that the main purpose of the shroud/level alternatives is so that you can group with your friends, but if I was not getting any XP at all, I would think twice about doing it.
Anyone investigated this further?