ActionScript 3.0 :: HTTPService Does Not Accurately Retrieves All Data

I'm using mx.rpc.http.HTTPService to retrieve data from a web service. On the initial call to "loadWsData", HTTPService accurately retrieves all the data. However, on any and all subsequent calls HTTPService does not accurately retrieve the data; rather it some how always retrieves the first data set. I've confirmed that the web service is providing accurate data, both from web browsers and a ruby ws client script. If I terminate the flex app and restart it, it will retrieve the accurate data.

ActionScript Code:
private function loadWsData():void{
var webService:HTTPService = new HTTPService();
webService.url = serviceUrl;
webService.method = "GET"; 
webService.addEventListener(ResultEvent.RESULT, function(event:ResultEvent):void{
var rawData:String = String(event.result);
var user:Object = JSON.decode(rawData).user;});
webService.send();}