So I've got a party consisting of a 10 Barbarian/Mythic Tier 2 with an 8 Oracle of Life Leadership Cohort, also Mythic Tier 2, another 10 Barbarian/Mythic Tier 2 (This one's built around defense, whereas the first Barb is entirely damage-dealing) and a Fighter 6/Oracle of Battle 4/Mythic Tier 2 in my party at the moment.
My problem is, the party seems to walk through every combat I can think of for them. The first barbarian slashes the hell out of everything with his Keen falchion and his healbot Oracle cohort channels positive energy every turn, usually without even moving from her spot. The other Barbarian is built around being an iron wall of defense with a 15-foot reaching spear, and the fighter is there to pick up the pieces.
I'm looking for a couple bits of advice. First, what cr should I be designing encounters for them? From what I can figure the APL of the group is 11, using the method described in the Core Rulebook. If I add the Leadership cohort's levels to the party that would bump the APL up to 13. Should I be including the levels of a Leadership cohort when I'm determining the APL? And what kinds of encounters do you guys suggest to provide a challenging, but fun experience for the players?
Thanks for all the help!