Helldritch
Hero
A lot of combats at my table overflow the 10 rounds mark. The more characters you have in your group, the more monsters/enemies you'll have to throw at them. Thus you'll get longer battles. My NPCs tends to use tactical combat maneuvers such as dodge and the help action to give archers/casters and whatever a better chance at hitting players and to survive longer to effectively block the players from going against bosses and ranged attackers. Of course it all depends on the terrain types and whether or not it is possible to make a choke point.