hi Paul,
I just checked the SCX 700 personality file it looks correct. So I do not understand why they are not moving smoothly in Cuelux. The only thing I can think of is that these scanners have 8-bit movement only, so that is why you could perhaps see some 'steps'.
My guess is that you will see the same behaviour in CueluxPro, as these two programs share most of the same software engine.
Are the scanners moving smoothly with a different controller?