Move layer to specific height (Y) px value (not translate)

This seems to work, although I must admit I'm not sure why. Firstly, is the "translate" method not just that, a translation from its current position as opposed to assigning a coordinate location? My canvas is 5400px in height, and when I use the following line you have recommended, it results in a Y-location of roughly 711px. How does this work?

app.activeDocument.activeLayer.translate(0, 400 - activeDocument.activeLayer.bounds[1].value);

Based on the above code line, in my mind this should move the layer from its current position by 400 - 5400 = -5000 px. Then if I were to run it again, it would move another -5000px. This is not the case, however, and does accomplish what I want (a stationary position).

I'm curious as to what's happening here. Regardless though, thanks for the solution!

Or perhaps something like​ this?

var savedRuler = app.preferences.rulerUnits;
app.preferences.rulerUnits = Units.PIXELS;
app.activeDocument.activeLayer.applyOffset(0, 100, OffsetUndefinedAreas.WRAPAROUND);
app.preferences.rulerUnits = savedRuler;