I'm not really sure how I should tackle this one. I could just put a check 'if this is a spritefont' then i'll tween the characterScale instead of tweening the instance size. However, this is not a very good solution, because then I should also tackle all other plugin type like text, etc.
About adding three scale options for litetween, that would make it more complicated, I really don't want people sets up more and more option when they are doing tween. LiteTween was meant to be simple and essential, adding more and more settings and feature will really bloat this in no time. For now I think I would just leave it out for now and go revisit this later on.