I am using the chaos perk “Advanced Techniques” which increased damage and resource cost of base core skills by 10 percent per rank. And when I am in town, my core skill (Frozen orb) indeed shows as costing 113 mana, which is what I wanted, so I could proc Banished lord every 3 attacks. But when I leave town, the resource cost reverts to it’s original cost. So I assume the perk is just disabled outside of town and the damage increase is not present either.