Inaba, I found that cutting back the pressure node will take care of most of the hard shift/clunk. It seems to depend on driving style of the said driver. I believe I have mine set between 35-40 now. Works out well for me. I get a hard shift/clunk every now and then, but that's usually in heavy traffic when I am going between 2nd to first. The Interceptor may not be very traffic friendly.

I would just toy with the pressure until you find a suitable setting.