MySQL Fulltext and scores.

Hello,
I am trying to understand why my fulltext queries are returning these scores, they don't make sense to me.

First off, here is my fulltext create

ALTER TABLE main ADD FULLTEXT(col1, col2, col3);

Code (markup):

In my table i have

main('Hello world / even more stuff', '', '')
main('Hello world / even more stuff', 'testing', 'tester')
main('Hello world / even more stuff', 'Hello world', 'Hello world')

Code (markup):

Now here is my query that gets the scores

SELECT
	MATCH(col1, col2, col3) AGAINST('+"hello world"' IN BOOLEAN MODE) as blnScore,
	MATCH(col1, col2, col3) AGAINST('hello world') as intScore

FROM
	main
WHERE
	MATCH(col1, col2, col3) AGAINST('hello world')
ORDER BY blnScore DESC, intScore DESC

Code (markup):

You would think that the row with 'Hello world' in every column would have the highest score, since the index is on every column, but that is not the case.

main('Hello world / even more stuff', '', '') //Score - 6.48660516738892
main('Hello world / even more stuff', 'testing', 'tester') //Score - 6.34852838516235
main('Hello world / even more stuff', 'Hello world', 'Hello world') //Score - 3.5588550567627

Code (markup):

Any ideas of what the problem could be?