Thats how I've been adding them , here's an example of a flat terrain grid and waypoint addition -
#grid add 100 2 2 (creates grid 100 with random waypoint, random pause time)
#wp add 100 45 1 (adds waypoint 1 , with 45 sec. delay to grid 100)
#wp add 100 45 2 (adds waypoint 2 , with 45 sec delay to grid 100)
etc...
you do need to add the waypoints in individually, I use the admin tool and refresh alot to keep track of waypoints and grids
Hope this helps a bit.