Did you implement the code for the communication with the controller directly in the callback functions of the GUI? This would be a pity.
Prefer to keep the data, the code for the calculations and the GUIs separated as clear as possible. Then you can modify each of them independent from the other parts. In your case this would have the advantage, that you can call the function for the communication directly without the need of the indirection over the GUI. The callback from the GUI would grab the values of its elements only, and call the external function for the processing.
I recommend to split the code of your GUI callbacks, because this is easier, more flexible and less prone to bugs, than some code to "remote control" the GUI and calling the callbacks magically with constructed inputs.
