Not sure that everyone understands the "grab channels" concept. In the picture below (last one linked above) the grab channels or deck channels are shallow concaves cut in the deck. I was talking with Chase at the worlds in '06 and he indicated that they helped him hold his grabs longer.
They also offer a structural enhancement to the board, they stiffen up the rail line without the added cost or weight of a stringer.
It's very similar to a piece of aluminum. Flat stock can bend in either direction if it's long enough. However, channeled stock is significantly harder to bend in either direction. This simple but elegant solution via the groove reduces the rail twist-off.
Really like the way you handled that Jerry.