I first designed a filled doll dressform which I printed for $53.70. Then I tried making it cheaper by hollowing it out in Blender. But when I uploaded the hollow version I noticed the preview showed it as filled and the price jumped to $71.56! I'm hoping someone here can enlighten me why this happened. I'm wondering if it is due to my limited skill with Blender that I did something wrong (not closing all shapes or something)? I've attached the original print and hollow versions of the dressform. Any help is greatly appreciated!!