how score() function works in HANA fuzzy search

Hi, i am confused by the score() returned value when i use this in fuzzy search in HANA

CREATE COLUMN TABLE test_similar_calculation_mode

( id INTEGER PRIMARY KEY, s text);

INSERT INTO test_similar_calculation_mode VALUES ('1','stringg');

INSERT INTO test_similar_calculation_mode VALUES ('2','string theory');

INSERT INTO test_similar_calculation_mode VALUES ('3','this is a very very very long string');

INSERT INTO test_similar_calculation_mode VALUES ('4','this is another very long string');

SELECT TO_INT(SCORE()*100)/100 AS score, id, s FROM test_similar_calculation_mode WHERE CONTAINS(s, 'theory', FUZZY(0.9, 'similarCalculationMode=compare')) ORDER BY score DESC;

the returned list is just as below

SCORE      ID      S

0.84            2       string theory

why i assign 0.9 as threshold in fuzzy function while this line with score 0.84 also be returned.

from my understanding, the S field is text data type, so the string actually is divided into seperate word list, so the score should be 1.0, is it right?

any hints is very appreciate,thanks