CS6 assign a point problem

I am using İndesign CS 6

With this command a text frame does not stop at the exact location

but When I give a space position comes to

how this problem can be solved

var box1 = app.selection[0].texts[0].insertionPoints.item(-1).textFrames.add();
box1.geometricBounds = [0, 0, 8, 5];
box1.anchoredObjectSettings.anchorYoffset = 0.15;
var txt = box1.texts[0].insertionPoints.item(-1).contents = "A";
box1.texts[0].pointSize = 21;
box1.fit(FitOptions.FRAME_TO_CONTENT);