Tibia and Fascia aren't quite the same artwork, they're simply made via the same method. That method being unique doesn't mean the pieces are any less distinct.
In short order, Tibia is a practical piece. It reacts to stimuli, and can change itself depending on the situation, but being made from Callisto's body specifically isn't important to the meaning. It's made that way because this was his masterpiece, and so he needed to use the material he knew best to make sure it came out the best it could.
With Fascia, being made from the artist is a fundamental aspect. It's a philosophical piece asking if all the pieces of a human, arranged differently but otherwise untouched, is still a human, maybe even the same person. Fascia could've been any non-human shape, and the fundamentals of the piece would be the same.