BLE: unexplained delay while WriteCharacteristic (XE8)

Hello, 

in an App for Andriod an iOS i use TBluetoothLEManager to communicate between mobile and a BLE-Device. 

To send data to the BLE-device, i use the code-sequence:       

CR_GattService:=FBLEDevice.GetService(CR_SERVICE);

CR_GattCharact:=CR_GattService.GetCharacteristic(CR_CHARACTERISTIC);  

CR_GattCharact.SetValue(sOutBuffer);   

sTime:=Now;    

TabbedForm.mDevOut.Lines.Add(SecondOf(sTime).ToString');

FBLEDevice.WriteCharacteristic(CR_GattCharact); 

sTime:=Now;    

TabbedForm.mDevOut.Lines.Add(SecondOf(sTime).ToString'); 

If I send a single command to the BLE-Device, the time between CR_GattCharact.

SetValue and FBLEDevice.WriteCharacteristic is about 200ms.  

When I send two command on behind the other, the time to write chracteristics is 3s?? 

Has anybody an explanation for that?(Android 4.4.2, on iOS this delay do not exist)  

Best Markus