Optimal XP for 6+ boxes

[Sam DeathWalker]

How do you explain that you've been at it for 2.5 years, and still have 2 thirds (23 out of 36) of your toons under 58 (16 under 50 even),

My byzantinely complex and sophisticated labyrinthine plan to make my opponents overconfident prior to their ignominious defeat is clearly paying off.