Likely the last tech who did the last brake job is trigger happy on the impact, they don't need to be that tight. Most people overtighten everything on a car, when a lower torque is better for the part, and is easier to break loose next time. You can simulate an impact by holding the wrench/ratchet on with one hand, and giving the wrench a hard, sudden hit, make sure you're going the right way, but that never fails in breaking them loose.