In my post in the battlemap sticky the horse charges where against spears and not pikes, pikes seem to have hidden bonuses that counter a charge with heavy damage, did you make the same tests with spears or any other melee unit, in any case my tests were more focused on the receiving bit of charges as the player with a melee unit but if I recall correctly I ran a series of 5 tests of mailed knights charging in a loose formation against spears and they did not do better than a tight charge.