The response time to a Bluetooth connection between Arduino and Android is proportional to the distance?

Question

I'm trying to get the distance between an Android device and a Arduino. To do this, I thought I'd use the formula of calculating networks latency, as seen in this link:

How to calculate packet time from latency and bandwidth

where the propagation time would be given to obtaining the time I spent to send a signal to the Arduino and get the answer divided by 2 (one-way time care). However, the time I have got varies even when not moving the Android device, and even increasing the distance, remains in the same range, between 1 and 11 milliseconds. My idea is wrong or the way I am doing it? I can even make these deductions have I done? Here is my code:

My button click

public void onLedOnClick(View v)
{
    long avg = 0;

    for(int i = 1; i < 31; i++){

        long t1 = System.currentTimeMillis();
        sendData("1");
        beginListenForData();
        long t2 = System.currentTimeMillis();

        avg = (avg + (t2-t1)) / i;

        txtAnswerTime.setText("Answer time:" + String.valueOf((t2-t1)) + "ms");
    }
    sendData("3");

}

my sendData method:

public void sendData(String data){
    if (btSocket != null) {
        try {
        // allows the output data from a socket
        outStream = btSocket.getOutputStream();
        } catch (IOException e) {
            Toast.makeText(getApplicationContext(), "Error: "+e.getMessage(), Toast.LENGTH_SHORT).show();
        }
        String mensagem = data;
        byte[] msgBuffer = mensagem.getBytes();     

        try {
        // sends content by bluetooth

        outStream.write(msgBuffer);
        } catch (IOException e) {
            Toast.makeText(getApplicationContext(), "Error: "+e.getMessage(), Toast.LENGTH_SHORT).show();

        }
    } else {
        Toast.makeText(getApplicationContext(),
        "Bluetooth is not connected", Toast.LENGTH_SHORT).show();
        }
}

My getData method:

public void beginListenForData()
{
    if (btSocket != null) {
            final Handler handler = new Handler(); 
            final byte delimiter = 10; //This is the ASCII code for a newline character

            stopWorker = false;
            readBufferPosition = 0;
            readBuffer = new byte[1024];
            try {
                mmInputStream = btSocket.getInputStream();
            } catch (IOException e) {
                e.printStackTrace();
            }
            workerThread = new Thread(new Runnable()
            {
                public void run()
                {                
                   while(!Thread.currentThread().isInterrupted() && !stopWorker)
                   {
                        try 
                        {
                            int bytesAvailable = mmInputStream.available();                        
                            if(bytesAvailable > 0)
                            {
                                byte[] packetBytes = new byte[bytesAvailable];
                                mmInputStream.read(packetBytes);
                                for(int i=0;i<bytesAvailable;i++)
                                {
                                    byte b = packetBytes[i];
                                    if(b == delimiter)
                                    {
                                         byte[] encodedBytes = new byte[readBufferPosition];
                                         System.arraycopy(readBuffer, 0, encodedBytes, 0, encodedBytes.length);
                                         final String data = new String(encodedBytes, "US-ASCII");
                                         readBufferPosition = 0;

                                        handler.post(new Runnable()
                                        {
                                            public void run()
                                            {
                                                txtBytesSize.setText("Received data: "+data);
                                            }
                                        });
                                    }
                                    else
                                    {
                                        readBuffer[readBufferPosition++] = b;
                                    }
                                }
                            }
                        } 
                        catch (IOException ex) 
                        {
                            stopWorker = true;
                        }
                   }
                }
            });

            workerThread.start();

    } else {
        Toast.makeText(getApplicationContext(),
        "Bluetooth is not connected", Toast.LENGTH_SHORT).show();
        }
}

My Arduino code:

const int ledPin = 7;   
byte serialA;         
void setup()
{

  Serial.begin(9600); 
  pinMode(ledPin, OUTPUT);
  digitalWrite(ledPin, LOW);
}

void loop() {

if (Serial.available() > 0) {serialA = Serial.read();Serial.println(serialA);}

  switch (serialA) {
case 49://49 is the bytes of "1"
  digitalWrite(ledPin, HIGH);
  Serial.println(serialA);
  break;

case 50: //50 is the bytes of "2"
  digitalWrite(ledPin, LOW);
  Serial.println(serialA);
  break;

  break;
  }

}