Tone Shift will give vastly difference results depending on the voice you use, I think. I am not sure the best way to describe it- i would recommend for any parameter to turn it all the way up or all the way down on a whole file and listen to it alone. try each extreme to maybe understand it best?
i would describe each as...
Tension: low means soft/whispery. high means tense/stronger. you can use it to bring some power to a voice or to soften them for whispery parts. this is not the same as Tone Shift, as Tone Shift takes into account the voice's tone at a certain pitch, where as Tension manipulates it to put an effect that it is stronger or softer.
Tone Shift: shifts the tone of the voice higher or lower (not the pitch- just the tone). for example, if the voice has a certain tone at a low register, you can bring that tone to the voice on any notes by lowering it in the parameter. its hard to explain but when i use a voice like Solaria, for example maybe her lower pitch tone is more of a chest voice that I want, and on the pitch she's at she doesn't get that. so If i lower the tone shift parameter on those notes, she will sing with a tone more like her lower pitch tone. on the opposite i could make it higher to bring in Solaria's head voice on any other notes regardless of pitch.
as i said though, it is really dependent on the voice. I think Solaria has the most obvious change with tone shift, and some other AI banks, but its not too obvious on some.
