Apart from that everything is OK.
Get a copy of http://www.netfabb.com/basic.php
It will check, repair, measure and scale. It will also show the volume.
On this model. Top - 141.31 cm3.
Middle - 319.33 cm3. One wall is showing up as 6mm thick.
Bottom - 181.09 cm 3
Box complete - 645.73 cm3