actually no that's not the way upkeep worked, due to the backspin placed on the mine (it was a mine, not a bomb as most people say) she "stuck" to the inside face of the dam, when she exploded, she would crack the dam, all the water pressure would then cause the dam to colapse, very clever really.................
and as far as bombs go, the Grand Slam and her family were about as accurate as you could get, they were amoung the very few bombs to be deigned with aerodynamics so much at the forfront, the bomb itself did actually have allot to do with accuracy...........