Materialise Challenge

For Code Breakers:
With the changes that Shapeways made to their pricing a few years ago now, it wasn't too long before some one managed to break their algorithm and find out how they were pricing (combination of bonding box and shrink wrapping with additional software to take large cavities into account).
Has anyone managed to do the same for materialise? Would be pretty interesting to have a comparison, but it has stumped me slightly. There is a strong trend of price vs bounding box volume, but past this, I can't quite work out what they're doing.
Pretty tricky challenge I know, but let me know if you crack it!