Right, just +1, and only if your Discipline is better than the other skill to begin with.
It's actually a supernatural power, not a stunt, so it should be a bit better than a mortal stunt. The guideline is 2 shifts of effect per point of refresh. Of course, that guideline also says that a STUNT shouldn't give a flat +2 to an attack skill.
There's also the guideline that says a [-1] power should be a little more potent for that 1 point, because a pure mortal taking a single [-1] power loses that +2 refresh bonus.
Maybe you have to invest minimum [-2] refresh, and get 3 skills for those first 2 points of refresh, then one for one after that.
Then again, you have to keep your skills set up just so to benefit from this, so maybe that satisfies the "under limited circumstances" clause of the stunt guideline.
Another possibility, one version of the power gives you Discipline complements Fists OR Weapons for [-1], another version lets Discipline complement two skills from the full list for [-1] but restricts Fist and Weapons to non-attack uses.