Adding a chord symbol from a plugin at a position where there is no note.

I’m writing a plugin that would embellish the harmony of a jazz lead sheet. In other words, it wants to add new suitable chord symbols halfway between existing ones where appropriate.
This works when there is a note at this position, but not when there is no note. In that case the new chord symbol gets added at the next note (see attached: added symbol in red).
test.mscz

I borrowed this code from another plugin:

function setCursorToTime(cursor, time){
cursor.rewind(0);
while (cursor.segment) {
var current_time = cursor.tick;
if(current_time>=time){
return true;
}
cursor.next();
}
cursor.rewind(0);
return false;
}// end setcursor To Time

var harmony = newElement(Element.HARMONY);
harmony.text = newchord;
setCursorToTime(cursor, newtime); //newtime = 960 in the example
cursor.add(harmony);

Neither cursor.next (or segment.next) ‘stops’ at this empty space.
Any suggestions? All help appreciated.