Haxe.io.bytes and setInt32()

I hope someone can reveal my error in reasoning.
I’m trying to put some integers into haxe.io.bytes using setInt32.

package;

import openfl.display.Sprite;
import openfl.Lib;
import haxe.io.Bytes;

class Main extends Sprite 
{

	public function new() 
	{
		super();
		var bytes:Bytes = Bytes.alloc(8);
		bytes.setInt32(0, -320);
		bytes.setInt32(1, -100);
		trace(bytes.getInt32(0),bytes.getInt32(1));
	}

}

What on earth causes the following output:
Main.hx:16: -25408,-100

Edit: Nevermind!
Obviously the index isn’t simply incremented by one continuously.
So:

		bytes.setInt32(0, -320);
		bytes.setInt32(4, -100);
		trace(bytes.getInt32(0),bytes.getInt32(4));

works as expected.

You can also use openfl.utils.ByteArray:

var bytes = new ByteArray ();
bytes.writeInt (-320);
bytes.writeInt (-100);

bytes.position = 0;
trace (bytes.readInt (),bytes.readInt ());