Both - sort of.
The first one will count a player's top 10 scores out of any number of tournaments played. So, if the player has played in 5 tournaments, all 5 will be included. If he has played in 12, the top 10 will be included. If he has played in 50, the top 10 will be included. This one can be described as "sums the top 10 [or fewer] scores".
The second one will drop the bottom 2 scores. If a player has played in 5 tournaments, the top 3 will be included. If he has played in 12, the top 10 will be included. If he has played in 50, the top 48 will be included. This one can be described as "sums all scores after dropping the lowest 2".