According to that page stabeth played passed it (2) be right on (4) hacked off (2) piripiriatetics (1) and commies (2).
Drop piripiri and be right on and you get 6.
Or are you asking why drop the top and bottom? At a guess I assume it 'normalises' you tie score on the assumption that if you need the tie, you probably got beaten by your top ranked opponent and won against your lowest ranked? Just a guess though.
According to that page stabeth played passed it (2) be right on (4) hacked off (2) piripiriatetics (1) and commies (2).
Drop piripiri and be right on and you get 6.
Or are you asking why drop the top and bottom? At a guess I assume it 'normalises' you tie score on the assumption that if you need the tie, you probably got beaten by your top ranked opponent and won against your lowest ranked? Just a guess though.