There is an excellent section in one book that covers the formulas needed to predict the flutter speed of a wing structure. Along it's tedious and winding way, it considers the pitching moment of the airfoil. Cutting to the bottom line, different airfoils have different pitching moments, and the results of the computations will be different for different airfoils. Two ideas stand out from that simple fact.



Change the airfoil and the flutter speed changes. (An airfoil with no aileron gap is a "different airfoil" from the same airfoil with a gap.)

Change the airflow over a wing/aileron system, and you've realistically got a different airfoil.