A score of 6.5 is easier to get than a score of 7.0. A score of 7.0 means that a test taker must score a level 7 in all four speaking criteria.
However, a 6.5 can get a score of 6.0 in two categories like grammar and vocabulary while getting a 7.0 in the other two categories. This means that you can have better speaking skills in grammar and/or vocabulary while having weaker skills in pronunciation and fluency or vice versa.
I have helped 1000s of students reach their scores and I can help you.