Probably true. In my initial post I mentioned I have some success in gripping the racquet differently, which I imagine changes the angle of the racquet face as it hits the ball (assuming all other things are equal). In some respects it's the same result as imagining hitting a different part of the ball.
I'm not sure which would work best though: changing the grip (physical 100% change), or visualising hitting a different part of the ball (mental change, which may lead to a physical change in the swing). Will need to test both