Switching between Waypoint and Heading, Speed, Altitude in GUIDED

I am working on controlling the aircraft (currently running the sim_vehicle.py sim) via a companion computer using the MAV_CMD_DO_REPOSITION and MAV_CMD_DO_CHANGE_SPEED commands for waypoint control, and MAV_CMD_GUIDED_CHANGE_SPEED, MAV_CMD_GUIDED_CHANGE_ALTITUDE, and MAV_CMD_GUIDED_CHANGE_HEADING commands for HSA control. The intention is to be able to switch from sending lla+speed commands to heading, speed, altitude commands, and back.

What I am running into is that the MAV_CMD_GUIDED_X commands appear to effectively override the MAV_CMD_DO_REPOSITION and MAV_CMD_DO_CHANGE_SPEED commands, with the result that once I have sent the former the aircraft no longer responds to the latter until I switch out of GUIDED and then back in. What I am seeing is that the Waypoint and Speed commands are Ack’d and Accepted, but the aircraft continues flying to the old HSA commands.

Is this the intended functionality? Is there any way to de-prioritize or clear the previously sent MAV_CMD_GUIDED_X commands once I want to start sending the MAV_CMD_DO_REPOSITION commands, without leaving GUIDED?