Since you are requesting only 30 results, if there are more than 30 flights in the specified range then it is not guaranteed which 30 you will receive (and may potentially different 30 each time you reload).
Also keep in mind that the lat/lon range filtering is considering only the most recent position of that flight, not all past positions of a flight.
the problem is that the query results do not match the results that it is flightware page, ilera aircraft appears to make no sense (as in the picture so that)
I don’t understand what your image is attempting to show as being incorrect. FlightXML uses the same data backend that is used for the maps on our website (though our maps do not use FlightXML as the interface).
Also, if you are simply trying to make an airport traffic display, you might want to consider a free trial of our FlightAware TV product: flightaware.com/commercial/tv/