If you create a From-Face plane from a curved-surface face, then the preview will give you the "tangent plane" with regards to the point selected—the subtype will conveniently default to Tangent Plane. This plane is specially marked as "dead" and will never be regenerated after creation. This is AGP Release 6.1 behavior and is maintained in the DesignModeler application Release 8.1 for backward compatibility. However, the correct way to create a tangent plane at a given point is to:
Place a controlled/persistent/parameterized Construction Point onto the face, via the Point Feature; and
Use this point feature points (PF points) for the tangent plane creation with the From-Point-and-Normal plane type.