I think that, [_grp,0] setwaypoint... Indicates the default waypoint created at the spawn of the unit.https://community.bistudio.com/wiki/setCurrentWaypoint has a note to that effect in its comments. This differs from how the editor assigns waypoint indices for display. If it's the first waypoint you add with commands it is [_grp, 1] setWaypoint.. Etc. Hope that helps.
Slightly odd, talks to pixels