Prevent cloth simulation shape key from adding to weights

So basically I made a shirt for a character via cloth simulation, converted it to the base shape and weight it to an armature.

What I’m trying to do is make corrective shapes for the shirt using cloth simulation instead of modeling or sculpting. When I convert a cloth simulation to a shape key and set it to max, it just adds to the transform of each vertex that is weighed by the armature.

Is there a way for the simulation to take the weights into account?