Had to really think this one through to picture what I do! And I would do it like AAM said. Lowering the inside hand and raising the outside.
Two things going on here... First... a dressage horse bending and the kind of contact and position of the hands is much more subtle in dressage than what you will do, you can tell that from the pics AAM posted. and what you do and the type of contact might be giving the same effect as doing it 'correct'. But I would say this... When you are in a lope and you bring the inside hand in and down, you allow the horse the inside, with a low head as the place to go, which is what you want. Leaving the ouside rein higher acts as the opposite. Especially with the tie-down you guys use, a high outside hand leaves him no where to go on the outside. The door is closed if the horse can't go that way. I would wonder if the tie-downs you guys use barrel racing interferes a little with bending, because they will often run tight against it, using it to balance, which makes for a hard rather than soft neck.