How to implement Audio disposal in C2 for use in Cocoon?

Acts.prototype.UnloadByName = function (filename)
{
	// only unload if we are in CocoonJS
	if (this.runtime.isCocoonJs)
	{
		var src = this.runtime.files_subfolder + filename.toLowerCase() + (useOgg ? ".ogg" : ".m4a");
		
		// unload it
		var instance = this.unloadAudioInstance(src);
	}
}

instanceProto.unloadAudioInstance = function (src_)
{
	// Try to find existing instance from the same source
	var i, len, a;		
	var bufferToDispose, instanceObjectToDispose;
	var foundInstance = 0;
	
	for (i = 0, len = audioInstances.length; i < len; i++)
	{
		a = audioInstances[i];
		
		if (a.src === src_ && (a.canBeRecycled() || is_music))
		{
			// DEBUG:
			console.log("Found instance");
			
			// locate existing instance's objects
			bufferToDispose = a.buffer.bufferObject;
			instanceObjectToDispose = a.instanceObject;
			foundInstance = 1;
			
			// now remove this audio instance completely and free it up for 
			// garbage collection using iterative array slice code on Scirra blog:
			// https://www.scirra.com/blog/76/how-to-write-low-garbage-real-time-javascript
			for (var x = i, newLen = len - 1; x < newLen; x++)
			{
				audioInstances[x] = audioInstances[x + 1];
			}
			audioInstances.length = newLen;
			
			console.log("Length is now: " + audioInstances.length);
			
			// we're done with this loop
			break;
		}
	}
	
	// now there are no references to audio, dispose it using Canvas+ dispose overload
	if (foundInstance == 1)
	{
		bufferToDispose.dispose();
		instanceObjectToDispose.dispose();
		console.log("Disposed it.");
	}
};
[/code:2hb21i2u]
Now I'm sure I didn't do it perfectly, because I don't yet completely understand how Audio works, but I tried to make sure to dispose of anything that could potentially contain loaded audio (i.e the "buffer" and the "instanceObject"). I made a test project which uses this function, and here's what I have working (in essence):

There are about 30 individual voice clips that can be loaded. To load a voice clip, you select it and then either Press "Play" or "Preload". Both seem to do the same thing in terms of loading a clip into memory. To unload a voice clip, you select it and then press "Unload". Now, here is what happens when I try it out:

At program start, memory use stabilizes at around: [b]72.14 mb[/b]

Once I load all 30 clips into memory, I get: [b]88.70 mb[/b]

After I unload all of them, I get: [b]81.50 mb[/b]

After loading all 30 again, I get: [b]81.64 mb[/b]

At this point, no matter what I do, memory stays: [b]81.64 mb[/b]

My question, to anyone that knows anything about memory or anything about Cocoon or Construct 2 Audio, such as @Ashley or @Ludei:

What exactly could be happening here? Why is it that when I unload everything, only half of the allocated space is released? Is there one more secret Audio object that I didn't dispose of? How come once I've unloaded them the memory use doesn't change much? What am I not understanding? I feel like the answer lies in how Ludei's engine works, or how Construct 2 works. I hope either the developers or someone else knowledgeable in this can help me, so I can start better managing memory in my game.

Thanks!