GT rule - A round ends when one player plays the final bone in his or her hand, or when the boneyard is empty and no player has a valid play. At that time, the player with the fewest points on the bones in his or her hand is the winner of the round. That player scores one point.

Let me see if this explains the rule better. 1st of all, you don't get a point for playing your last bone. It only ends the round. Then, you count the pips in each hand. In this case both hands had no pips. So therefor each player gets a point. One player went from 53 to 54. The other player went from 60 to 61 ending the game. It is perfectly clear to me that playing your last bone does not give you a point. Playing your last bone will give you a point if the other player has a bone that has pips on it.