BROADCAST FINALS ABC:  SHARK TANK dropped 0.09 to 0.56, and 20/20 was down 0.04 to 0.40. CBS:  UNDERCOVER BOSS fell 0.09 to 0.33, MAGNUM PI lost 0.04 to 0.45, and BLUE BLOODS was down 0.06 to 0.47. NBC:  After a rerun...