Also at least it seemed that the 6 starships in question were a Galaxy-class with a group (perhaps 5) of Excelsior class vessels. With the Galaxy being amongst the heaviest hitters in Starfleet and Excelsiors being among the stronger ships as well makes for a fairly strong mix up. Remember that even though the Klingon fleet was 50 ships, I wouldn't be surprised if a decent number were small light ships like B'rel-class Bird of Preys.