In the beginning of the video Blue Origin New Shepard self-landing rocket launch with 38 research payloads (5/2/2019) the announcer mentions that both the tilting fins and the BE-3 engine nozzle gimbal are used to control the direction of the rocket.
How are these two very different methods use? Is one used at low speeds or high atmospheric pressure and the other used at high speed or low pressure? Or do they work in combination, on different timescales, or with one serving as a "trim" to the other?