They only work on mob kill experience. Mob exp in the open world is pitiful.
They don't work on Dungeon Bosses. The Developers decided to remove mob exp from dungeons.
They don't work in Bozja.
Checkmate, SE. Well done (heavy sarcasm)
Edit: I was noticing both Levelling Roulette and MSQ were giving lower exp results than expected and I think the loss of mob exp is the reason why.
Basically SE needs to re-tune some numbers.