Flash :: AS3 Using Sound.extract In A Loop To Analyse A Soundfile?

From this AS3 code I expect 500 lines of trace outputs that contain "2048". But instead I get only some lines containing "2048". The rest of the traces print a "0" which shows me that the extract() method did not return any data.

Why is this the case? I would like to iterate through the soundfile with a specific amount of steps to extract 2048 bytes of the sound at the respective position. Extracting the entire soundfile at once would freeze the flashplayer for seconds and is therefore not a good solution for me.This behaviour can be found as long steps is smaller than samplesInSound/2048.The closer it comes to that value, the more lines with a "0" are printed compared to those with a 2048 in it.

var sound:Sound = new Sound();
sound.load(new URLRequest("soundfile.mp3"));
sound.addEventListener(Event.COMPLETE, soundLoaded);[code].....

I had the idea that the extracted part of the soundfile is cut out of the rest of the soundfile after extracting it (like at Actionscript 3 - Sound.extract method empties sound object data), so I tried out another for loop:

for(var i=0; i<samplesInSound - steps * 2048; i += Math.floor(samplesInSound/steps) - 2048) but this didn't work out either.