According to the author of 1 Chronicles, this verse talks about a brave man who was the leader of a group, and he was more special than two other men. However, he was not as famous or important as the top three leaders.
1 Chronicles 11:21: Of the three, he was more honourable than the two; for he was their captain: howbeit he attained not to the [first] three.
This verse states that Benaiah was not among "three mighties," contradicting the special honor given in 1 Chronicles 11:21.
1 Chronicles 27:6: This [is that] Benaiah, [who was] mighty [among] the thirty, and above the thirty: and in his course [was] Ammizabad his son.