The horizontal correction at the end was part of the plan. I suspect the purpose is to come in at an angle so that the direction of the final correction is appr

The horizontal correction at the end was part of the plan. I suspect the purpose is to come in at an angle so that the direction of the final correction is approximately known, and they can correct only by varying the amount of thrust, not the direction of the thrust (which is presumably slower). Vs. coming in right on target - you'll still have small corrections to make at the end, but you have to gimbal the thruster in a random direction.