This is incorrect. There is usually a huge delay before any motion happens. The speed of that motion is independent of the planning speed. If you have to replan

This is incorrect. There is usually a huge delay before any motion happens. The speed of that motion is independent of the planning speed. If you have to replan during a move then yes the two can become intermingled, but if you watch most ROS based planning today what you see is a good 30 seconds of compute before the robot moves at all. Sometimes it can be multiple minutes!